Composite laminate has enjoyed a wide application in aerospace structures, thus the reinforcement of the cutout has always been concerned. Composite laminate with large opening under three different load cases: tension, shear and compress were investigated. The optimization design of different types of reinforcement with different materials was also conducted. The parameters of reinforced structure were optimized to satisfy the objective weight function, and the multi-level optimization method was adopted during the optimization process. The weight characteristics of reinforced structure were also compared and analyzed. The results show that under different load cases, compared with bolt connection reinforcement and co-curing reinforcement, intercalation reinforcement is better with the minimum weight increase.