diff --git a/func/Module_preprocess.py b/func/Module_preprocess.py
index bb96559..7652406 100644
--- a/func/Module_preprocess.py
+++ b/func/Module_preprocess.py
@@ -20,6 +20,7 @@ from func.utils.PublicFunc import PublicFunc
 from func.utils.Constants import Constants
 from func.Filters.Preprocessing import Butterworth_for_BCG_PreProcess, Butterworth_for_ECG_PreProcess
 from func.utils.Result import Result
+from func.utils.FloatingImagePanel import add_floating_image_panel
 
 from ui.MainWindow.MainWindow_preprocess import Ui_MainWindow_preprocess
 from ui.setting.preprocess_input_setting import Ui_MainWindow_preprocess_input_setting
@@ -187,6 +188,12 @@ class MainWindow_preprocess(QMainWindow):
         self.progressbar = None
         PublicFunc.add_progressbar(self)
 
+        self.image_overlay = add_floating_image_panel(
+            self.centralWidget(),
+            title="参考图例",
+            img_path=r"image\legend_preprocess.png"
+        )
+
         self.plot_mode = plot_mode
         if self.plot_mode == "matplotlib":
             #初始化画框
@@ -492,6 +499,18 @@ class MainWindow_preprocess(QMainWindow):
             self.ax0.grid(True)
             self.ax0.xaxis.set_major_formatter(Params.FORMATTER)
 
+    def update_overlay_position(self):
+        """手动定位函数"""
+        margin = 20
+        x = self.width() - self.image_overlay.width() - margin
+        y = margin
+        self.image_overlay.move(x, y)
+
+    def resizeEvent(self, event):
+        """确保窗口变大小时，悬浮窗依然在右上角"""
+        super().resizeEvent(event)
+        self.update_overlay_position()
+
 
 class Data:
 
diff --git a/func/utils/FloatingImagePanel.py b/func/utils/FloatingImagePanel.py
new file mode 100644
index 0000000..4a0862b
--- /dev/null
+++ b/func/utils/FloatingImagePanel.py
@@ -0,0 +1,95 @@
+from PySide6 import QtWidgets, QtCore, QtGui
+
+
+class FloatingImagePanel(QtWidgets.QWidget):
+    def __init__(self, parent, title="原始比例预览", image_path=None):
+        super().__init__(parent)
+        self.is_expanded = True
+
+        # 1. 样式配置 (保持深色风格，方便看清信号)
+        self.setAttribute(QtCore.Qt.WA_StyledBackground, True)
+        self.setStyleSheet("""
+            FloatingImagePanel {
+                background-color: rgba(30, 30, 30, 220);
+                border: 2px solid #444;
+                border-radius: 4px;
+            }
+            QLabel#title_label { color: #ffffff; font-weight: bold; font-family: 'Consolas'; }
+            QPushButton#toggle_btn { background: #444; color: white; border: none; }
+        """)
+
+        # 2. 布局初始化
+        self.main_layout = QtWidgets.QVBoxLayout(self)
+        self.main_layout.setContentsMargins(4, 4, 4, 4)
+        self.main_layout.setSpacing(2)
+
+        # --- 标题栏 ---
+        self.header = QtWidgets.QWidget()
+        header_layout = QtWidgets.QHBoxLayout(self.header)
+        header_layout.setContentsMargins(2, 2, 2, 2)
+
+        self.title_label = QtWidgets.QLabel(title)
+        self.title_label.setObjectName("title_label")
+        self.toggle_btn = QtWidgets.QPushButton("▲")
+        self.toggle_btn.setFixedSize(22, 22)
+
+        header_layout.addWidget(self.title_label)
+        header_layout.addStretch()
+        header_layout.addWidget(self.toggle_btn)
+        self.main_layout.addWidget(self.header)
+
+        # --- 图片展示区 ---
+        self.image_label = QtWidgets.QLabel()
+        # 关键点 1：关闭自动填充，确保我们手动控制尺寸
+        self.image_label.setScaledContents(False)
+        # 关键点 2：设置对齐方式为中心
+        self.image_label.setAlignment(QtCore.Qt.AlignCenter)
+        self.main_layout.addWidget(self.image_label)
+
+        # 3. 信号绑定
+        self.toggle_btn.clicked.connect(self.toggle_content)
+
+        # 4. 加载图片
+        if image_path:
+            self.update_image(image_path)
+
+    def update_image(self, path):
+        """完全根据图片的物理尺寸调整窗口"""
+        pixmap = QtGui.QPixmap(path)
+        if not pixmap.isNull():
+            # 拿到图片的原始宽高
+            w = pixmap.width()
+            h = pixmap.height()
+
+            # 强制 Label 等于图片大小
+            self.image_label.setFixedSize(w, h)
+            self.image_label.setPixmap(pixmap)
+
+            # 让整个窗口重新计算布局，贴合 Label
+            self.adjustSize()
+
+            # 保持展开状态
+            self.set_expanded(True)
+
+    def set_expanded(self, expanded: bool):
+        self.is_expanded = expanded
+        self.image_label.setVisible(expanded)
+        self.toggle_btn.setText("▲" if expanded else "▼")
+
+        # 关键点 3：重置窗口大小
+        # 展开时它会变大包住图片，收起时它会缩成标题栏大小
+        self.adjustSize()
+
+        # 通知父窗口刷新位置，防止因为变大而超出右边界
+        if hasattr(self.parent(), 'update_overlay_position'):
+            self.parent().update_overlay_position()
+
+    def toggle_content(self):
+        self.set_expanded(not self.is_expanded)
+
+
+# --- 封装的调用函数 ---
+def add_floating_image_panel(parent_widget, title="图片原尺寸", img_path=None):
+    panel = FloatingImagePanel(parent_widget, title, img_path)
+    panel.raise_()
+    return panel
\ No newline at end of file
diff --git a/image/legend_preprocess.png b/image/legend_preprocess.png
new file mode 100644
index 0000000..ee697f4
Binary files /dev/null and b/image/legend_preprocess.png differ