Abstract: The effect of the addition of reinforcing particles on the casting properties of metal matrix composites was studied by numerical simulation. A database of ProCAST was developed based on the function equation between the volume fraction of reinforcing particles and physical property parameters. Gravity die casting of motorcycle wheels was taken as an example to study the casting property of the 5% Al₂O₃ particle reinforced aluminum matrix composites. The calculated results indicate that the fluidity of the aluminum matrix composites tends to decrease because of the addition of the particles. Melt viscosity of the composite is higher than A356.2. Shrinkage porosity defect appears both in the spoke and rim of the wheel. The mass fraction of silicon is enhanced by 7.5% in the allowed range. The temperature interval from pouring temperature to liquidus temperature can be increased and the crystallization temperature interval can be reduced synchronously. The latent heat of fusion is increased，so as to shorten the solid-liquid coexistence time，enhancing the fluidity of melt and feeding capacity. The shrinkage porosity defect in the spoke and rim of the wheel is decreased and eliminated.