diff --git a/app/src/main/java/io/legado/app/data/entities/Book.kt b/app/src/main/java/io/legado/app/data/entities/Book.kt
index 318fb8a88..5b61a6cc7 100644
--- a/app/src/main/java/io/legado/app/data/entities/Book.kt
+++ b/app/src/main/java/io/legado/app/data/entities/Book.kt
@@ -94,8 +94,12 @@ data class Book(
         GSON.fromJsonObject<HashMap<String, String>>(variable) ?: HashMap()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
         variable = GSON.toJson(variableMap)
     }
 
diff --git a/app/src/main/java/io/legado/app/data/entities/BookChapter.kt b/app/src/main/java/io/legado/app/data/entities/BookChapter.kt
index dc0aa7951..bd02b125f 100644
--- a/app/src/main/java/io/legado/app/data/entities/BookChapter.kt
+++ b/app/src/main/java/io/legado/app/data/entities/BookChapter.kt
@@ -49,8 +49,12 @@ data class BookChapter(
         GSON.fromJsonObject<HashMap<String, String>>(variable) ?: HashMap()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
         variable = GSON.toJson(variableMap)
     }
 
diff --git a/app/src/main/java/io/legado/app/data/entities/RssArticle.kt b/app/src/main/java/io/legado/app/data/entities/RssArticle.kt
index 9e0f91b2d..911fb16b8 100644
--- a/app/src/main/java/io/legado/app/data/entities/RssArticle.kt
+++ b/app/src/main/java/io/legado/app/data/entities/RssArticle.kt
@@ -40,8 +40,12 @@ data class RssArticle(
         GSON.fromJsonObject<HashMap<String, String>>(variable) ?: HashMap()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
         variable = GSON.toJson(variableMap)
     }
 
diff --git a/app/src/main/java/io/legado/app/data/entities/RssStar.kt b/app/src/main/java/io/legado/app/data/entities/RssStar.kt
index dcd8ea737..df4bd546f 100644
--- a/app/src/main/java/io/legado/app/data/entities/RssStar.kt
+++ b/app/src/main/java/io/legado/app/data/entities/RssStar.kt
@@ -32,8 +32,12 @@ data class RssStar(
         GSON.fromJsonObject<HashMap<String, String>>(variable) ?: HashMap()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
         variable = GSON.toJson(variableMap)
     }
 
diff --git a/app/src/main/java/io/legado/app/data/entities/SearchBook.kt b/app/src/main/java/io/legado/app/data/entities/SearchBook.kt
index 70896b9da..96c525b3a 100644
--- a/app/src/main/java/io/legado/app/data/entities/SearchBook.kt
+++ b/app/src/main/java/io/legado/app/data/entities/SearchBook.kt
@@ -63,8 +63,12 @@ data class SearchBook(
         GSON.fromJsonObject<HashMap<String, String>>(variable) ?: HashMap()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
         variable = GSON.toJson(variableMap)
     }
 
diff --git a/app/src/main/java/io/legado/app/model/analyzeRule/RuleData.kt b/app/src/main/java/io/legado/app/model/analyzeRule/RuleData.kt
index b26e43715..3752ac113 100644
--- a/app/src/main/java/io/legado/app/model/analyzeRule/RuleData.kt
+++ b/app/src/main/java/io/legado/app/model/analyzeRule/RuleData.kt
@@ -6,8 +6,12 @@ class RuleData : RuleDataInterface {
         hashMapOf<String, String>()
     }
 
-    override fun putVariable(key: String, value: String) {
-        variableMap[key] = value
+    override fun putVariable(key: String, value: String?) {
+        if (value != null) {
+            variableMap[key] = value
+        } else {
+            variableMap.remove(key)
+        }
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt b/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
index 80bf658f6..8b87f949b 100644
--- a/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
+++ b/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
@@ -4,6 +4,10 @@ interface RuleDataInterface {
 
     val variableMap: HashMap<String, String>
 
-    fun putVariable(key: String, value: String)
+    fun putVariable(key: String, value: String?)
+
+    fun getVariable(key: String): String? {
+        return variableMap[key]
+    }
 
 }
\ No newline at end of file
diff --git a/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt b/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
index d6f4a8cc4..ce9a16923 100644
--- a/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
@@ -122,6 +122,8 @@ class BookInfoActivity :
             !viewModel.bookSource?.loginUrl.isNullOrBlank()
         menu.findItem(R.id.menu_set_source_variable)?.isVisible =
             viewModel.bookSource != null
+        menu.findItem(R.id.menu_set_book_variable)?.isVisible =
+            viewModel.bookSource != null
         return super.onMenuOpened(featureId, menu)
     }
 
@@ -161,6 +163,7 @@ class BookInfoActivity :
             }
             R.id.menu_top -> viewModel.topBook()
             R.id.menu_set_source_variable -> setSourceVariable()
+            R.id.menu_set_book_variable -> setBookVariable()
             R.id.menu_copy_book_url -> viewModel.bookData.value?.bookUrl?.let {
                 sendToClip(it)
             } ?: toastOnUi(R.string.no_book)
@@ -336,7 +339,31 @@ class BookInfoActivity :
                 }
             }.show()
         }
+    }
 
+    private fun setBookVariable() {
+        launch {
+            val variable = withContext(IO) { viewModel.bookData.value?.getVariable("custom") }
+            alert(R.string.set_source_variable) {
+                setMessage("""书籍变量可在js中通过book.getVariable("custom")获取""")
+                val alertBinding = DialogEditTextBinding.inflate(layoutInflater).apply {
+                    editView.hint = "book variable"
+                    editView.setText(variable)
+                }
+                customView { alertBinding.root }
+                okButton {
+                    viewModel.bookData.value
+                        ?.putVariable("custom", alertBinding.editView.text?.toString())
+                    viewModel.saveBook()
+                }
+                cancelButton()
+                neutralButton(R.string.delete) {
+                    viewModel.bookData.value
+                        ?.putVariable("custom", null)
+                    viewModel.saveBook()
+                }
+            }.show()
+        }
     }
 
     @SuppressLint("InflateParams")
diff --git a/app/src/main/res/menu/book_info.xml b/app/src/main/res/menu/book_info.xml
index 37acb0fa3..b2d1657ce 100644
--- a/app/src/main/res/menu/book_info.xml
+++ b/app/src/main/res/menu/book_info.xml
@@ -34,6 +34,11 @@
         android:title="@string/set_source_variable"
         app:showAsAction="never" />
 
+    <item
+        android:id="@+id/menu_set_book_variable"
+        android:title="@string/set_book_variable"
+        app:showAsAction="never" />
+
     <item
         android:id="@+id/menu_copy_book_url"
         android:title="@string/copy_book_url"
diff --git a/app/src/main/res/values-es-rES/strings.xml b/app/src/main/res/values-es-rES/strings.xml
index 131c3f1a5..29db8c859 100644
--- a/app/src/main/res/values-es-rES/strings.xml
+++ b/app/src/main/res/values-es-rES/strings.xml
@@ -873,4 +873,5 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 </resources>
diff --git a/app/src/main/res/values-ja-rJP/strings.xml b/app/src/main/res/values-ja-rJP/strings.xml
index 572840413..75bf1aab9 100644
--- a/app/src/main/res/values-ja-rJP/strings.xml
+++ b/app/src/main/res/values-ja-rJP/strings.xml
@@ -873,4 +873,5 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 </resources>
diff --git a/app/src/main/res/values-pt-rBR/strings.xml b/app/src/main/res/values-pt-rBR/strings.xml
index 93ad6d6b0..192b5742b 100644
--- a/app/src/main/res/values-pt-rBR/strings.xml
+++ b/app/src/main/res/values-pt-rBR/strings.xml
@@ -873,5 +873,6 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 
 </resources>
diff --git a/app/src/main/res/values-zh-rHK/strings.xml b/app/src/main/res/values-zh-rHK/strings.xml
index f6f79fe01..f60da25d3 100644
--- a/app/src/main/res/values-zh-rHK/strings.xml
+++ b/app/src/main/res/values-zh-rHK/strings.xml
@@ -870,5 +870,6 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 
 </resources>
diff --git a/app/src/main/res/values-zh-rTW/strings.xml b/app/src/main/res/values-zh-rTW/strings.xml
index 49f5841bc..3102efc92 100644
--- a/app/src/main/res/values-zh-rTW/strings.xml
+++ b/app/src/main/res/values-zh-rTW/strings.xml
@@ -871,5 +871,6 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 
 </resources>
diff --git a/app/src/main/res/values-zh/strings.xml b/app/src/main/res/values-zh/strings.xml
index f32c7c762..aa291b690 100644
--- a/app/src/main/res/values-zh/strings.xml
+++ b/app/src/main/res/values-zh/strings.xml
@@ -872,5 +872,6 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 
 </resources>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index e437d54b9..f1a46592a 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -873,5 +873,6 @@
     <string name="direct_link_upload_rule_summary">用于导出书源书单时生成直链url</string>
     <string name="copy_play_url">拷贝播放Url</string>
     <string name="set_source_variable">设置源变量</string>
+    <string name="set_book_variable">设置书籍变量</string>
 
 </resources>