The influence of modified materials on the moisture absorption and thermal conductivity of raw soil blocks was studied by dynamic test and steady state flat plate method. The results show that the initial moisture absorption ratio, equilibrium moisture content and 60h moisture absorption ratio increases with the increase of relative humidity. When the relative humidity is 40% and 60%, the equilibrium moisture content of composite modified raw soil block is greater than that of lime and cement modified raw soil blocks. The thermal conductivity of raw soil block increases with the increase of equilibrium moisture content. The equilibrium moisture content, thermal conductivity and dry density of lime modified and composite modified raw soil block increase with the increase of lime content and fiber content. The equilibrium moisture content of cement modified raw soil block decreases with the increase of cement content, which is opposite to the change trend of thermal conductivity and dry density.