Bolt joint is one of the most important connection forms in mechanical structures. Reasonable bolt position distribution can effectively reduce bolt load, but there is still a lack of relevant optimization design methods. This paper presents a method suitable for bolt position optimization of complex structures. In the method, firstly, the perforated region is discretized to obta in coordinates of the nodes on the boundary of design region then expressed in polar coordinates. Bolts’ positions are also expressed by pole diameter and pole angle.The design variable consists of pale diameter and pole angle. The constraint condition is determined by the polar diameter and polar angle of the design area boundary. Design objectives are determined by the designer. The design objective adopted in this paper is to minimize the variance of bolt load. Then, parametric samples and batch simulations are carried out in the design space to generate data sets, and a proxy model was constructed. The spider monkey optimization algorithm is used to optimize the location of bolt. Finally, using the optimization method of this paper,a program is written, and the corresponding calculation example is given. The results show that the proposed method can effectively optimize bolt position.