Micro milling is a new method for machining micro parts. In order to study the change rule of cutting temperature field in micro-milling process, the thermal-mechanical model of micro milling was established by using finite element analysis software. The influence of cutting parameters, milling mode and friction coefficient on the cutting temperature field is analyzed by simulating the micro-milling process and verified by orthogonal test. The results show that the simulation results are consistent with the experimental results. The spindle speed has the most significant effect on the cutting temperature, followed by the feed speed, and the amount of depth cutting is the least obvious; In the two different machining methods of forward milling and reverse milling, the reverse milling has a greater influence on the cutting temperature; when the friction coefficient is small, the range of cutting temperature rise is large, whereas the range of cutting temperature rise is small. The research results have certain guiding significance for the actual micro-milling.