Abstract: In view of complex optimization problems in actual engineering, it is usually difficult to obtain the display function relationship expression between the optimization design variables and the optimization goals. This paper takes the column of the SZJY-14 machining center as the research object, and studies a technology based on a combined approximate model optimized design of the column structure.First of all, for the low prediction accuracy of the radial basis basis approximation model, a multi-strategy based radial basis approximation model technology is studied, and based on the improved radial basis basis approximation model technology, a combined approximation model technology is constructed; secondly, The finite element analysis software Abaqus was used to mesh the three-dimensional structure of the column, and the static and dynamic performance analysis was performed to determine the optimization target, and the sensitivity analysis method was used to determine the optimization design variables, and the combined approximate model technology was used to establish the column optimization model; finally, The improved backtracking search optimization algorithm is adopted to realize the optimization design of the column structure. The solution results show that compared with the original structure of the column, the optimized mass is reduced by 3.77%, the maximum deformation is reduced by 5.14%, and the first-order frequency is increased by 5.9%, achieving the expected effect.