New model SiC preform made up of SiC foam and SiC particle, SiC foam / particle / Al hybrid composites （V sic=53%, 56%, 59. 9%） for electronic packaging substrate were fabricated by squeeze casting technology. The thermal conductivity of SiC foam/SiCp/Al hybrid composites on the room temperature was higher than 130 W/（m ·℃）because of the special double interpenetrating structure of composites. With increase of the temperature, the specific heat capacity of composites was increased, the thermal diffusivity and the thermal conductivity was decreased. But with the con- tent of SiC reinforcement in the composites, the specific heat capacity was linearly decreased, the thermal diffusivity and the thermal conductivity of composites was fell nonlinearly because of the effect of the thermal barrier at the interface of composites.