Abstract: SiC/Al composites were prepared by pressureless infiltration using domestic abrasive grade SiC particles with average diameters in the range of 60-80 μm. The fine particles and organics absorbed on the SiC particles were cleaned successively by different cleaning methods to investigate theirs effects on the microstructure and mechanical properties of the SiC/Al composite. The results show that the surface of SiC particles can be cleaned by deionized water and acetone. The defects in the corresponding SiC/Al composite are reduced effectively, with the mechanical properties being (347.48±29.87)MPa and(348.39±4.40)MPa, respectively.Acetone can effectively remove the adsorbed particles and organics on the surface of SiC particles, resulting in the whole enhanced wettability of particles and molten aluminum solution, the internal defects of the composite are the least, and the mechanical properties of the material are the best.