The spindle is a crucial component in a horizontal machining center,and optimizing its design can significantly enhance the center′s dynamic performance and motion accuracy.Based on the finite element analysis results of the spindle,several design variables were considered,including the front and rear radii and lengths of the spindle and the outer diameter of the pull rod.The optimization goals were to minimize the total mass and total maximum deformation while maximizing the first-order natural frequency.The CCD experimental design method was used to obtain initial sample points,and a response surface was established using the Kriging model.Finally,a multi-objective genetic algorithm (MOGA) was used for optimization.The results show that by using the proposed method,the spindle mass is reduced by 29.6%,total deformation decreases by 30.8%,and the first-order natural frequency increases by 5.4%.