High volume fraction (63vol.%) SiCp/Al composite for electronic packaging fabricated by pressureless infiltration was characterized by microscopy, physical and mechanical tests. Microscopy observations and XRD analysis indicated that the composite appeared to be free of porosity and macroscopically homogeneous, SiC-Al interface was atomic bonding interface with low thermal resistivity and electrical resistivity, no interfacial reaction products was detected. Examination of the fracture surfaces of the composites revealed that the cracks passed through the SiC particles and Al matrix, no debonding of SiC-Al interface was observed. The fracture mode indicated that the bonding between SiC-Al was sufficient strong. The properties of the composite were noted for its ultrahigh thermal conductivity of 235W/m·K and specific modulus (79.9×105m), low coefficient of thermal expansion (7.2×10-6/K) and density of 2.99g/cm3. The advantages of the composite over traditional materials used as the electronic packages for aerospace applications were analyzed.