Abstract: By squeeze casting technology , industrial pure aluminum L2 , LD11 (Al-12 %Si) and AlSi20 (Al-(18～21) %Si) alloys were reinforced with SiC particles of 20μm and 60μm. And their thermal conduction properties were investigated. On the basis of equal specific interfacial areas , an equivalent particle diameter is brought forward and the thermal conductivity of dual-sized particles reinforced aluminum matrix composites is calculated. The SiC_P/ Al composites possess relatively excellent thermal properties , and the thermal conductivities of LD11 and AlSi20 matrix composites are larger than those of matrices. This is attributed to the fact that the equivalent particle diameter of SiC is larger than its criticaldiameter and the thermal conductivity of SiC is higher than those of LD11 and AlSi20. But the thermal conductivities ofSiC_P/ Al composites decrease with the increasing of Si additions to the matrix.