In order to process workpieces with a diameter of 320 mm and a height of 250 mm,a five-axis direct-drive compound machining center with mineral materials for the bed and gantry frame was designed while ensuring various contact dimensions.In order to reduce the weight of the machine tool and reduce its center of gravity,the mineral material gantry frame was designed to improve the modal performance and minimize the flexibility as the goal of topology optimization design,and then the multi-objective genetic algorithm was used to optimize the size of the topologically optimized gantry frame.And its dynamic and static performance was carried out simulation analysis and comparison many times before and after.Compared with the existing cast iron gantry frame in the market and the finally optimized mineral material gantry frame,the results show that the quality of the mineral material gantry frame decreases by 15.03%,the maximum deformation decreases by 8.7%,the maximum stress decreases by 56.68%,and the first order natural frequency increases by 23.45%.The optimized mineral material gantry frame is significantly better than the cast iron gantry frame support in terms of static and dynamic characteristics and lightweight.