Abstract: Considering two factors of tool wear and environment temperature in milling process,the influence of three main parameters,cutting depth,federate,and spindle speed on the surface roughness of the workpiece after milling is studied in this paper.Though the analysis of the experimental data,the change characteristics of surface roughness and signal-to-noise ratio of each factor at different levels are studied on the basis of Taguchi design method.The influence degree of different milling parameters on the surface roughness of the workpiece is analyzed,and the optimized milling parameters are obtained.The experimental results show that the influence degree of the surface roughness on the workpiece surface is in turn the spindle speed,the feed and the cutting depth,and the minimum roughness of 0.8 m can be achieved by using the optimal milling parameters.The research method has reference significance for optimizing CNC milling parameters.