The effects of heat treatment on dry sliding wear properties for A356/20vol.% SiCp composites have been investigated. Various heat treatments were performed on A356/20vol.% SiCp composites; solution and/or aging treatment for improving mechanical properties of the materials, and low temperature annealing for improving electrical conductivity of the materials. Wear tests have been performed on as-cast and heat-treated samples. The results show that as-cast samples exhibited better resistance to wear than heat-treated samples. Through the observations and analysis of the worn surface, worn subsurface and wear debris, the effect of heat treatment on dry sliding wear properties for A356/20vol.% SiCp composites has been examined. The decrease of wear properties for heat treatment samples is related with the change of microstructural features such as eutectic Si morphology, decrease of electrical conductivity, and occurrence of interfacial reactions between matrix and reinforcing particles.