diff --git a/app/src/main/java/io/legado/app/model/WebBook.kt b/app/src/main/java/io/legado/app/model/WebBook.kt
index a09e9f326..9201fd542 100644
--- a/app/src/main/java/io/legado/app/model/WebBook.kt
+++ b/app/src/main/java/io/legado/app/model/WebBook.kt
@@ -11,6 +11,8 @@ import io.legado.app.model.webbook.BookContent
 import io.legado.app.model.webbook.BookInfo
 import io.legado.app.model.webbook.BookList
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlin.coroutines.CoroutineContext
 
 class WebBook(val bookSource: BookSource) {
 
@@ -20,9 +22,13 @@ class WebBook(val bookSource: BookSource) {
     /**
      * 搜索
      */
-    fun searchBook(key: String, page: Int? = 1, scope: CoroutineScope = Coroutine.DEFAULT)
-            : Coroutine<List<SearchBook>> {
-        return Coroutine.async(scope) {
+    fun searchBook(
+        key: String,
+        page: Int? = 1,
+        scope: CoroutineScope = Coroutine.DEFAULT,
+        context: CoroutineContext = Dispatchers.IO
+    ): Coroutine<List<SearchBook>> {
+        return Coroutine.async(scope, context) {
             bookSource.searchUrl?.let { searchUrl ->
                 val analyzeUrl = AnalyzeUrl(
                     ruleUrl = searchUrl,
@@ -40,9 +46,13 @@ class WebBook(val bookSource: BookSource) {
     /**
      * 发现
      */
-    fun exploreBook(url: String, page: Int? = 1, scope: CoroutineScope = Coroutine.DEFAULT)
-            : Coroutine<List<SearchBook>> {
-        return Coroutine.async(scope) {
+    fun exploreBook(
+        url: String,
+        page: Int? = 1,
+        scope: CoroutineScope = Coroutine.DEFAULT,
+        context: CoroutineContext = Dispatchers.IO
+    ): Coroutine<List<SearchBook>> {
+        return Coroutine.async(scope, context) {
             val analyzeUrl = AnalyzeUrl(
                 ruleUrl = url,
                 page = page,
@@ -57,8 +67,12 @@ class WebBook(val bookSource: BookSource) {
     /**
      * 书籍信息
      */
-    fun getBookInfo(book: Book, scope: CoroutineScope = Coroutine.DEFAULT): Coroutine<Book> {
-        return Coroutine.async(scope) {
+    fun getBookInfo(
+        book: Book,
+        scope: CoroutineScope = Coroutine.DEFAULT,
+        context: CoroutineContext = Dispatchers.IO
+    ): Coroutine<Book> {
+        return Coroutine.async(scope, context) {
             val analyzeUrl = AnalyzeUrl(
                 book = book,
                 ruleUrl = book.bookUrl,
@@ -76,9 +90,10 @@ class WebBook(val bookSource: BookSource) {
      */
     fun getChapterList(
         book: Book,
-        scope: CoroutineScope = Coroutine.DEFAULT
+        scope: CoroutineScope = Coroutine.DEFAULT,
+        context: CoroutineContext = Dispatchers.IO
     ): Coroutine<List<BookChapter>> {
-        return Coroutine.async(scope) {
+        return Coroutine.async(scope, context) {
             val analyzeUrl = AnalyzeUrl(
                 book = book,
                 ruleUrl = book.tocUrl,
@@ -97,9 +112,10 @@ class WebBook(val bookSource: BookSource) {
         book: Book,
         bookChapter: BookChapter,
         nextChapterUrl: String? = null,
-        scope: CoroutineScope = Coroutine.DEFAULT
+        scope: CoroutineScope = Coroutine.DEFAULT,
+        context: CoroutineContext = Dispatchers.IO
     ): Coroutine<String> {
-        return Coroutine.async(scope) {
+        return Coroutine.async(scope, context) {
             val analyzeUrl =
                 AnalyzeUrl(
                     book = book,
diff --git a/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt b/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
index b754f91f1..a9e84bf0d 100644
--- a/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
+++ b/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
@@ -29,12 +29,17 @@ class SearchViewModel(application: Application) : BaseViewModel(application) {
         searchKey = key
         startTime = System.currentTimeMillis()
         start?.invoke()
-        task = execute(context = searchPool) {
+        task = execute {
             //onCleared时自动取消
             val bookSourceList = App.db.bookSourceDao().allEnabled
             for (item in bookSourceList) {
                 //task取消时自动取消 by （scope = this@execute）
-                WebBook(item).searchBook(key, searchPage, scope = this@execute)
+                WebBook(item).searchBook(
+                    key,
+                    searchPage,
+                    scope = this@execute,
+                    context = searchPool
+                )
                     .timeout(30000L)
                     .onSuccess(Dispatchers.IO) {
                         it?.let { list ->
diff --git a/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceViewModel.kt b/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceViewModel.kt
index 265dcc227..9843ec994 100644
--- a/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceViewModel.kt
+++ b/app/src/main/java/io/legado/app/ui/changesource/ChangeSourceViewModel.kt
@@ -54,12 +54,12 @@ class ChangeSourceViewModel(application: Application) : BaseViewModel(applicatio
     }
 
     fun search() {
-        task = execute(context = searchPool) {
+        task = execute {
             searchStateData.postValue(true)
             val bookSourceList = App.db.bookSourceDao().allEnabled
             for (item in bookSourceList) {
                 //task取消时自动取消 by （scope = this@execute）
-                WebBook(item).searchBook(name, scope = this@execute)
+                WebBook(item).searchBook(name, scope = this@execute, context = searchPool)
                     .timeout(30000L)
                     .onSuccess(IO) {
                         it?.forEach { searchBook ->