Abstract: Abstract The coefficient of thermal expansion and thermal conductivity of the squeeze casting SiC_w/Al composites were measured and analyzed. The experimental results showed that with the increasing temperature, the coefficients of thermal expansion of both SiC_w/Al composite and aluminium alloy are increased. The coefficient of thermal expansion of the T 6 state SiC_w/Al composite is lower than that of the as-cast composite, and the deep-cooled(-196℃) SiC_w/Al composite shows the lowest coefficient of thermal expansion. It is also found that with the increase of the whisker volumefraction, the coefficient of thermal expanlion of the SiC_w/Al composite is obviously decreased, and the thermal conductivity of the composite is also decreased.