Based on slip line and stacking fault appeared on the silicon surface, the dislocation theory is used to analyze the reasons of causing dislocation and stacking fault during the bending process and study their influence on the laser bending, according to the experiment of thin silicon laser bending. The analyzed results indicate that the slip line is caused by the dislocation accumulation, and the stacking fault is the results of piled dislocation. Meanwhile influence of the dislocation density and dislocation moving velocity on the process of laser bending is analyzed. The changing process of dislocation density and the deceased dislocation moving velocity are considered to form maximal angle.