Abstract: The rotary seat is an important component of the crusher. In order to reduce the weight of the structure and achieve lightweight design, finite element analysis is conducted on the rotary seat. The three-dimensional model of the rotary seat is constructed by using the SoildWorks software, and then it is imported into the finite element software ANSYS Workbench; The optimization objective is to minimize the total mass of the rotary seat under the condition of meeting the extreme working conditions. Through the topology optimization, the results show that while meeting the structural performance indicators, the total mass of the rotary seat is reduced by 8.59%, and the maximum stress and maximum deformation basically remain unchanged; thus it could effectively reduce the manufacturing costs.