在几何证明或求解中 ,作辅助线是常有的事 ,正确的辅助线使问题变得非常简单 ,思维变得十分顺畅 .如何捕捉辅助线的一些线索 ,仔细研究试题的已知、未知及图形的特征 ,对作辅助线大有裨益 ,本文着重以初二《三角形》中的一些例子加以剖析 ,因为《三角形》是几何学习开始较系统 In the geometrical proof or solution, the auxiliary line is a common thing. The correct auxiliary line makes the problem very simple and the thinking becomes very smooth. How to capture some clues to the auxiliary line and study carefully the known, unknown and The characteristics of the graphs are of great help for the auxiliary line. This article focuses on the analysis of some examples in the second triangle “Triangle” because the “triangle” is the starting point of geometric learning.