diff --git a/HFUTCourseSimulation/ImageExport.cs b/HFUTCourseSimulation/ImageExport.cs
index a917790..77aa623 100644
--- a/HFUTCourseSimulation/ImageExport.cs
+++ b/HFUTCourseSimulation/ImageExport.cs
@@ -92,7 +92,7 @@ namespace HFUTCourseSimulation {
                     var rect = new RectangleF(cellx * BodyCellWidth, celly * BodyCellHeight, BodyCellWidth, celly * BodyCellHeight);
                     graphics.DrawString(courses.Name, textFont, textBrush, rect);
                     var thisTextMargin = graphics.MeasureString(courses.Name, textFont, BodyCellWidth).Height;
-                    graphics.DrawString(courses.Desc, textFont, textBrush, cellx * BodyCellWidth, celly * BodyCellHeight + textMargin);
+                    graphics.DrawString(courses.Desc, textFont, textBrush, cellx * BodyCellWidth, celly * BodyCellHeight + thisTextMargin);
                 }
 
                 //reset