Abstract: In order to explore a new way to improve the comprehensive performance of machine tool, a new method of using steel-polypropylene fiber reinforced artificial granite composite (SPFRAG) instead of cast iron to make lathe bed is put forward. The SPFRAG bed structure was redesigned on the basis of a lathe bed, and the response surface model was established by using Kriging interpolation method, and the weight proportion was determined by sensitivity analysis of each design variable, based on the multi-objective genetic algorithm (MOGA) , the optimization of the bed structure is carried out with the constraints of the bed mass and the first natural frequency, and with the maximum total displacement and the maximum equivalent stress as the optimization objectives. The results show that the static and dynamic characteristics of SPFRAG bed are better than those of cast iron bed, which proves the feasibility of the scheme.