The design criteria of air exchange rates for venlo-type greenhouse was ranged from 0.7 to 0.8 min(ASAE, 1996). This standard is enough to maintain the ventilation rate temple Europe countries. However, a serious temperature and humidity gradient was found owing to the inadequateness of the air exchange rate. The difference of the air temperatures between pad and fan position was usually 6 to 8℃ in Summer.