The inner mast of Lifting equipment is selected as research contents,the Solidworks software is used as the 3D solid model establishment,then the model of inner mast is imported into ANSYS Workbench to finite element analysis and to get the equivalent deformation and stress contours clouds which the inner mast under the most dangerous condition,it's intensity and stiffness meet to the requirement of design.Then regard section size of column as design variables,its intensity and stiffness are constraints,the minimum mass is goal,multi-objective optimization design is carried out on the inner mast.The results show that not only the inner mast after optimization in quality is reduced by 12%,but also the static characteristics are improved,which provides reference for the improvement of the inner mast