For the problem of the tooth crown collapse angle in fine blanking of tooth parts，firstly, the geometric characteristics of tooth parts and characteristics of fine blanking were analyzed, and the relationship between these features and the collapse angle of tooth parts during fine blanking was also analyzed. Then, the deformation zone of fine blanking was divided into two core deformation zones and two deformation influencing zones, and the forming process of collapse angle in the core deformation zoneⅠwas analyzed. Furthermore, the flow law of material at the top of tooth during the forming process was found by the finite element simulation software Deform-3D. The results show that the material near the A surface at the top of tooth moves toward the top of tooth in a radial direction, and a part of material flows to the outside of the addendum. However, the material near the B and C sides flows along the contour line toward the top of tooth. Therefore, a variety of factors affecting the size of tooth crown collapse angle during fine blanking were analyzed again, and the influences of blank holder force and ejection force on the collapse angle were found out. So it is pointed out that the effect of ejection force is more significant than that of blank holder force on controlling collapse angle. Finally, the concrete measures to reduce or eliminate the tooth crown collapse angle during the fine blanking process of tooth parts were put forward.