The present work aims at simulating three-dimensional milling operation of aluminum allo7451.Building a nose ring radius and edge radius tool model. Using finite element analysis software , conducted a three-dimensional simulation of milling process. Milling force, milling temperature, stress distribution and chip shape of milling process have been got. A milling force experiment was carried out under the same cutting conditions as the simulation, and a good agreement between the simulation result and the experimental result was achieved, and chip shape matched the practice well. The simulation shows that the three-dimensional finite element milling cutter model and the workpiece model can be used to correctly simulate precision milling process, optimizing the cutting parameters by analyzing variation of the cutting force, the temperature and equivalent stress.