Three kinds of high volume fraction Sip/1199, Sip/4032 and Sip/4019 composites were fabricated by squeeze casting method. The results show that the clean Si/Al interfaces without interfacial reaction products can decrease the interfacial thermal resistance. The composites have a low coefficient of thermal expansion (7.5×10-6 ℃-1) and high thermal conductivity ranging from 126 to 157.9 W/(m ℃). With increasing temperature, the specific capacity and the average coefficient of thermal expansion increases monotonically, the thermal diffusivity and the thermal conductivity decrease gradually. The specific capacity, average coefficient of thermal expansion, thermal diffusivity and the thermal conductivity of the composites decrease gradually with increasing Si content.The thermal conductivities of composites were calculated by theoretical models. Both Maxwell model and P.G model consider the reinforcement as nearly-round particles, and the interface thermal resistance of Sip/Al composite calculated by EMA method is 0.01×10-6m2.℃/W