Abstract: 60 % SiCp/Al composites with a relative density of 98.7 % were successfully prepared by the combination of ceramic injection molding for the preparation of SiC preforms with monosized particles and aluminum pressureless infiltration technique. The composites' microstructures were uniform and dense observed by SEM. The coefficients of thermal expansion of the composites in the current work ranged from 7.10×10^-6 to 7.75×10^-6 K^-1 as the temperature from 100 ℃ to 400 ℃, and the thermal conductivity was 170 W·m^-1·K^-1. Both were suit the technique requirement for electronic packaging.