In order to improve structure property of the artillery cradle, satisfy the requirement of the structure lightweight design, and reduce the development cycle and development costs, a topology optimization design for the cradle structure is conducted in this article. Through choosing two of the most terrible sub cases which the artillery cradle bears, according to the force of the cradle, the finite element model based on Hypermesh-OptiStruct software can be obtained. By using topology optimization based on artificial material method, the geometric model of cradle can be obtained of which low density area is removed. Then in order to obtain the final optimization results, a Boolean sum operation is applied to the geometric model from two sub cases. Analysis results show that after the topology optimization, the stiffness of the cradle is higher than the one without optimization and the weight has some reduction. The result can satisfy the requirement of the artillery overall dynamic and static response.