There is currently no relevant national design standards about mast crane, so there are many of its non-standard design and a variety of forms and no attention is payed to the rationality of the design. Therefore, optimal design of the mast crane steel structure has a significant meaning for design technology of mast crane. This paper refers to a kind of parametric optimization model based on Ansys OPT, combined with finite element analysis (FEA) and stability theory. The building process and the program structure of the parametric optimization model is introduced. Corresponding program is developed by using ansys parametric design language (APDL) , which extract some parametes from FEA results, such as weight and axial force, etc, and rapid optimization design of mast crane is realized. It has a referenced meaning for optimization design of steel structure of all types of mast crane.