In order to quantify the effect of the wall greening to improve the thermal environment of the outside of the building, the outdoor experiment was done using greening panels. For the walls covered with the greening panels of different type and the concrete wall painted white, the quantity of radiation was measured by the reflected solar radiation and the long wave radiation. Then MRT was calculated from the result of the measurement and the radiation environment was evaluated.
As the result, from the measurement of surface temperature, the difference of the greening panels and concrete wall with white coat is not so significant in daytime. And for the reflected solar radiation, the figure at the wall covered with greening panels were constantly less than those at the concrete wall. At the maximum 62-65 % reduction were observed. Evaluating the comprehensive radiation environment by MRT , MRT was about 11°C reduced by the greening panels. The effectiveness of MRT as the evaluation index was suggested.