This paper presents a method for improving the cutting tool life by varying the feed throughout the milling process of Ti40 burn resistant titanium alloy. In this research, the model between tool life and the feed variation amplitude, period and step duration of the milling was constructed and the optimal feed variation parameters were selected. Experimental results show that the optimal sinusoidal feed milling parameters were 11.72 percent sinusoidal feed variation amplitude, with 120 seconds one period and 5 seconds incremental steps, which increase the cutting tool life by a maximum of 33 percent. In comparison with constant feed processes, variable feed milling changes the mechanism of the tool rake face by increasing the tool-chip contact area, change the crater position and decrease the crater wear depth, thus strengthens the tool edge and increases tool life.