Abstract: Based on so many experiments,authors found a system to lower the greenhouse temperature during the summer time by spraying the water on the film underneath the glass roof. The experiments showed that the system paid a very successful results in lowering the inside greenhouse temperture in the summer time.The advantages of this system in comparing with other systems are as follows: (1) high cooling efficiency; (2) low energy consumption; (3) easy to ins tall, remove and manage; and (4)low cost.The paper also discusses the relationships between the cooling efficiency and types of sprayer and also the materials of film and their spectral characters.