The method for calculating wall surface heat storage coefficient was introduced,and the coefficients of several common walls with light-weight external thermal insulation materials and the traditional solid clay brick wall were calculated.In order to study the impact of light-weight external thermal insulation materials,a contrasting experiment was carried out between an external insulated room and an uninsulated room in August,2010,in Chongqing,China.The result shows that outside surface heat storage coefficient of the insulated wall is much less than that of the traditional wall.However,during sunny time,the surface temperature of external walls of the insulated room is obviously higher than that of the uninsulated room.In different orientations,due to different amounts of solar radiation and being irradiated in different time,the contrasting temperature difference(CTD) appears different regularity.In a word,using light-weight external thermal insulation materials has a negative impact on building surrounding thermal environment and people’s health.Finally,some suggestions on how to eliminate the impact,such as improving the surface condition of the building envelop,and plating vertical greening,are put forward. The method for calculating wall surface heat storage coefficient was introduced, and the coefficients of several common walls with light-weight external thermal insulation materials and the traditional solid clay brick wall were calculated. In order to study the impact of light-weight external thermal insulation materials, a contrasting experiment was carried out between an external insulated room and an uninsulated room in August, 2010, in Chongqing, China. The result shows that outside surface heat storage coefficient of the insulated wall is much less than that of the traditional wall. However, during sunny time, the surface temperature of external walls of the insulated room is obviously higher than that of the uninsulated room. Different orientations, due to different amounts of solar radiation and being irradiated in different time, the contrasting temperature difference (CTD ) different differentity. In a word, using light-weight external thermal insulation materials has a negative impa ct on building surrounding thermal environment and people’s health .Finally, some suggestions on how to eliminate the impact, such as improving the surface condition of the building envelop, and plating vertical greening, are put forward.