For ensuring low cost and efficiency of canister, carry out optimization design for certain type rocket launcher canister. Based on satisfying design requirement, taking loss of weight as target, chose marching, launching and piling as typical working situation, used structure optimal design technology in HyperWorks to research optimal structure of canister model, optimal thickness of working pieces such as clamp plate, and clamp plate cross section shape. Based on this, completed canister optimal design. The analysis results show that the optimal design canister can satisfy performance requirements. It also verifies the feasibility of optimal design, and supplies canister loss weight research with the complete optimal design method. Compared with situation before optimization, the optimal canister weight decreased at the percentage of 20%.