Abstract: In order to study the influence of cutting parameters on the cutting force of high-speed milling of 20CrMnTi hardened steel, this paper adopts the orthogonal experimental method to conduct high-speed milling experiments. The collected raw data are processed, and the range analysis of the data results is conducted to obtain the impact of cutting parameters on the milling force and the optimal cutting parameters. The influence of cutting parameters on cutting force is obtained by using a single factor test method. The research results show that the milling depth is the primary factor affecting the cutting force F_x in the X direction during the milling process of hardened steel, with the feed per tooth having a relatively small impact, and the cutting speed having the smallest impact; For the Y direction cutting force F_y, the milling depth has the greatest impact, followed by the cutting speed, and the feed per tooth has the smallest impact. When the cutting speed increases from small to large, the cutting forces F_x and F_y decrease as the speed increases; When the feed rate per tooth increases from 0.05 mm/z to 0.13 mm/z, the cutting forces F_x and F_y show an upward trend; The cutting force F_y increases rapidly with the increase of the milling depth. Although the cutting force F_x also shows an upward trend, the growth rate is lower than F_y.