SiCp/1060A1, SiCp/ZL101, SiCp/ZL102 composites with SiCp volume fraction of 55% were fabricated by pressureless infiltration. The microstructure was examined and thermal properties were characterized for SiCp/Al composites. The results show that the composites are dense and macroscopically homogeneous. With the increase of temperature, the mean linear coefficient of thermal expansion(CTE) at 25-200 ℃ of the composites increases and ranges from 7.23×10-6 to 10.4×10-6 K-1, but thermal conductivity declines gradually at the same time. With the increase of Si content in the Al matrix, CTE of the composites declines and thermal conductivity also declines but not linearly, when Si content is up to 7%, the average thermal conductivity is 140.4 W/(m.K), which is close to that of the SiCp/1060Al composite (144.6 W/(m.K)). While Si content is 11.7%, the average thermal CTE and improving thermal conductivity of the composites. Compared with conventional thermal management materials, SiCp/Al composites are potential candidate materials for advanced electronic packaging due to their tailorable thermo-physical properties.