Mastering the quantitative relationship between the thermal conductivity and the moisture content of concretes is the premise of accurate calculations of envelope heat and mass transfer and energy consumption of the concrete building. The influence of the moisture content on the thermal conductivity of three concretes and the quantitative relationship between them was obtained by experimental analysis. The results show that the effect of moisture content on concretes thermal conductivity will be more obvious with the larger porosity. The thermal conductivity of the moist concretes increases quickly in a low moisture content range and increases slowly in a high moisture content range. This trend is more obvious at larger concretes porosities and pore diameters. The thermal conductivity is related to the moisture content of concretes through an approximate power function.