Abstract: The particle reinforced magnesium matrix composite is of great significance in the manufacture of piston. The service life of piston is closely related to the friction and wear properties of the material, so it can predict the wear resistance of magnesium matrix composite piston. Based on Archard wear model and adaptive mesh technology, a finite element model of SiC/AZ91D magnesium matrix composite and its matrix was established to explore its wear behavior under different loads, investigate its stress field distribution and wear depth, and conduct experimental verification to reveal the wear mechanism. The results show that, under different loads, the stress values of the nearest and furthest distance from the disc axis are larger on the contact surface of the disc pin, while other radial regions are smaller. With the increase of load, the stress values in all parts of the disc and pin contact area increase. Under different loads, the wear depth of the contact surface of the disc pin is smaller at the closest point to the disc axis, and the wear depth is larger and larger with the increase of the radial distance from the disc axis. With the increase of load, the wear depth increases in all parts of the disc and pin contact area. However, the wear depth of the composite is less than that of the matrix, which shows better wear resistance. Abrasive wear and peeling wear are the main wear mechanisms of the composite, adhesive wear is the main wear mechanism of the matrix alloy, and the simulation results are in good agreement with the experimental results.