In this paper, according to the different physical properties of each component of asphalt concrete, a finite element simulation is used to build a mechanical constitutive model for the concrete cutting processes. When the machine cutter contacts different aggregate particles, the variation rules of mechanical information are obtained and studied. The main research work includes: (1) The track and force of the tool in the cutting process are defined, and then the track equation of the tool tip and the calculation formula of friction resistance are obtained. The relationship between the friction resistance and working parameters is clarified. (2)From the multicompont modeling, the internal components of asphalt concrete are refined, and the mechanical properties of asphalt mortar and aggregate particles are set up. Random feeding of different aggregate particles in asphalt concrete specimens is completed by using Python software and Monte carlo method. After the simulation, the results are imported into numerical software to generate the variation curve of tool friction resistance, so as to obtain the rule of its change with various factors, and according to the above studies, the optimal working parameters combination of the milling planer are summarized.