In order to reduce the drilling temperature and axial force during skull drilling, a skull drilling model was established by using finite element simulation software ABAQUS to explore the influence rules of the main geometric parameters of fried dough twist drill on mechanical damage and thermal damage, such as apex angle, spiral angle, web thickness and cross edge angle. An optimized drill bit which could reduce mechanical damage and thermal damage was prepared and tested. The results show that the optimum geometric parameters of fried dough twist drill are apex angle is 96°, helix angle is 38.802°, web thickness is 0.8 mm and cross edge oblique angle is 131.018°; compared with the original bit, by using the optimized bit, the axial force and drilling temperature are lower.