Surface composites of WC reinforced steel matrix were fabricated by vacuum-expendable pattern casting (V-EPC) technology in order to provide theoretic direction for designing surface composites with high thermal fatigue performance, and then the thermo-physical properties of the composites, such as thermal expansion coefficients and thermal conductivities were characterized. The influence of process parameters on the thermo-physical characteristics was investigated. The results show that the thermal expansion coefficient the sampled layer decreased when the distance of which to the transition layer becomes lager. For the layers sampled at the same distance, their thermal expansion coefficient increased with the increase of WC particles size. For the surface composites reinforced with different sizes of WC particles, the thermal conductivities increased with the increasing temperature. When the temperature was higher (above 170℃), the thermal conductivities of the composites decreased with increase of the sizes of WC particles, and when the temperature was lower (40℃ and 105℃), the thermal conductivities of the composites did not change remarkably. The composite with Ni addition has lower thermal expansion coefficient and thermal conductivity than that of those without Ni.