This paper reports on an theoretical study of heat transfer from evaporative cooling system by the flow of recirculated water over the roof. In this system tile water is distributed at the top of the pitched roof, collected at the bottom by a gutter and recirculated by a pump. To analysis the system, the energy balance equations are developed and solved using a finite difference method. The calculation results show a good agreement with the measured ones obtained from our experiment. Based on the results, it was seen that the roof-evaporative cooling system reduced the heat flux significantly compared with the conventional roof structure even in the hot-humid summer climate of Korea.