Thermal conductivity of coarse aggregate, cement mortar as well as concrete were measured by the method of guarded hot plate apparatus and transient plane source. The influences of sand ratio, type and volume fraction of aggregate, water cement ratio and saturation degree were investigated. By use of the theoretical models for thermal conductivity of composite materials, interfacial thermal resistance between cement mortar and coarse aggregate in saturated and non saturated concrete were studied. The results show that thermal conductivity of concrete increases with the increment of saturation degree of concrete, volume fraction and thermal conductivity of aggregate, while decreases with the water cement ratio. The interfacial thermal resistance cannot be neglected for dry concrete. Finally, assuming that the thermal conductivity of solid phase in concrete increases linearly with saturation degree, a prediction model was proposed for thermal conductivity of concrete in consideration of saturation degree.