High-speed cutting technology is widely used in aviation, mold, automotive industries and other fields for its high machining efficiency, smaller cutting force, less cutting heat and high machining precision. However, the production site in China, high-speed machine tools do not really play its role in some enterprises, without real sense of the high-speed machining. Aluminum alloy 2A70 as the research object, using single-factor test, study the effect law of high-speed milling parameters on milling force here. The results show that: the cutting force is varying for high-speed milling, showing a periodic variation, with the transient characteristic, the milling force is large amplitude fluctuations in X and Y direction, the amount of change is respectively 55.544N and 56.306N. Milling force influenced by the spindle speed, with the increase of spindle speed, X contribute to the greatest change in the direction of milling, Y direction second, Z direction is almost unchanged. Under the experimental conditions, the stability high-speed cutting area of 2A70 is the spindle speed in the area of 21000rpm~27000rpm. The results of high-speed milling of aluminum alloy have certain significance.