Aiming at the problem of large thrust of hydraulic cylinder in the work of singlestage scissor lift platform,the mechanical model was established,and the relationship between the installation position of the hydraulic cylinder and the articulated position and thrust of the scissor arm was analyzed.The genetic algorithm combined with SQP method was put forward to optimize the installation position of the hydraulic cylinder.With the minimum thrust as the target,the optimization result was realized in MATLAB software.The results show that the thrust gotten by the this method is decreased 52% than that of the traditional genetic algorithm,while decreased 277% than that of the original method.So this method is effective,it provides certain reference for same type of optimization design.