Abstract: Aiming at the multi-objective optimization problem of milling parameters of CNC machine tools, a multi-objective optimization method for milling parameters of CNC machine tools with high efficiency and quality is proposed. Firstly, a multi-objective optimization scheme with cutting speed, feed per tooth, cutting depth and cutting width as optimization variables and minimum cutting force and maximum material removal rate as objectives is constructed. Then the chaos initialization multi- objective particle swarm optimization model based on tent map is used to optimize the parameters. Finally, the orthogonal experiment with four factors and four levels is established, and the results are compared with the optimized parameters. The experimental results show that the optimization scheme is feasible and the optimization model is reliable.