The red clay sintered porous face brick was selected as the research object. The moisture contents(by mass) of porous face brick at different soaking times were measured. At stable thermal and humid environment, the water evaporation amounts and moisture contents of porous face brick at different times were also tested. The influences of watering schemes on inner and outer surface temperatures and heat flows of wall were compared. The results show that the red clay sintered porous face brick is suitable for the water carrier during evaporation cooling of wall. In the stable thermal and humid environment, the critical moisture content of porous face brick is 31%. The inner and outer surface temperatures and heat flows of wall could be decreased significantly when the porous face brick is watered. With the increase of watering number, the lowest moisture content of porous face brick is ascend and the decreasing amplitudes of inner and outer surface temperatures and heat flows of wall are continuously rising. When the watering number increases to 8 times, the lowest moisture content of porous face brick will be greater than the critical moisture content, and the decreasing amplitudes of inner and outer surface temperatures and heat flows of wall tend to be stable. Therefore, the critical moisture content of porous face brick can be used as a criterion for watering to save water while facilitating the evaporative cooling effect.