diff --git a/reader/browser/PageRenderThread.cpp b/reader/browser/PageRenderThread.cpp
index 906f5da8..4c4c44d3 100644
--- a/reader/browser/PageRenderThread.cpp
+++ b/reader/browser/PageRenderThread.cpp
@@ -814,13 +814,17 @@ bool PageRenderThread::execNextDocPageThumbnailTask()
         return true;
     }
 
-    QImage image = task.renderer->getImage(task.index, 174, 174);
+    // 渲染分辨率需匹配显示侧实际尺寸(174 * pixScale * dpr),避免源图像被
+    // Qt painter 上采样放大导致模糊;pixScale 由 task 从 UI 层传入
+    int renderSize = static_cast<int>(174 * task.pixScale * dApp->devicePixelRatio());
+
+    QImage image = task.renderer->getImage(task.index, renderSize, renderSize);
 
     if (!image.isNull()) {
         // 预取图片对象 bbox(夜间/深色蒙版用):在工作线程取,避免 UI 线程与渲染争文档锁;
-        // 与 getImage 同尺寸(174,174)请求,蒙版与缩略图输出像素一一对齐
+        // 与 getImage 同尺寸请求,蒙版与缩略图输出像素一一对齐
         if (DocSheet::existSheetByUuid(task.uuid) && task.renderer->opened()) {
-            task.imageRects = task.renderer->getImageObjectRects(task.index, 174, 174);
+            task.imageRects = task.renderer->getImageObjectRects(task.index, renderSize, renderSize);
         }
         emit sigDocPageThumbnailTaskFinished(task, QPixmap::fromImage(image));
     }
diff --git a/reader/browser/PageRenderThread.h b/reader/browser/PageRenderThread.h
index 0b8ff46b..6215d407 100644
--- a/reader/browser/PageRenderThread.h
+++ b/reader/browser/PageRenderThread.h
@@ -83,6 +83,7 @@ struct DocPageThumbnailTask {//缩略图
     DocSheet *sheet = nullptr;
     SideBarImageViewModel *model = nullptr;
     int index = -1;
+    qreal pixScale = 1.0; //侧边栏缩放因子(adaptScale),渲染分辨率 = 174 * pixScale * dpr
     QVector<QRectF> imageRects; //图片对象 bbox(夜间/深色蒙版用,与缩略图像素对齐,worker线程预取)
 };
 
diff --git a/reader/sidebar/SideBarImageViewModel.cpp b/reader/sidebar/SideBarImageViewModel.cpp
index 3d64d743..9cb92f98 100644
--- a/reader/sidebar/SideBarImageViewModel.cpp
+++ b/reader/sidebar/SideBarImageViewModel.cpp
@@ -131,6 +131,7 @@ QVariant SideBarImageViewModel::data(const QModelIndex &index, int role) const
             task.model = const_cast<SideBarImageViewModel *>(this);
             task.renderer = m_sheet ? m_sheet->rendererPtr() : nullptr;
             task.uuid = m_sheet ? m_sheet->uuid() : QString();
+            task.pixScale = m_parent ? m_parent->property("adaptScale").toDouble() : 1.0;
             PageRenderThread::appendTask(task);
         }
 
@@ -204,6 +205,7 @@ void SideBarImageViewModel::onUpdateImage(int index)
     task.index = index;
     task.model = const_cast<SideBarImageViewModel *>(this);
     task.renderer = m_sheet ? m_sheet->rendererPtr() : nullptr;
+    task.pixScale = m_parent ? m_parent->property("adaptScale").toDouble() : 1.0;
     task.uuid = m_sheet ? m_sheet->uuid() : QString();
     PageRenderThread::appendTask(task);
     qCDebug(appLog) << "Updating image for index:" << index << "end";