A mathematical simulation model was developed to investigate the effectiveness of using a water film flowed on a shading cloth stretched over the greenhouse cover for greenhouse cooling. The microclimatic energy balance can simply be developed to predict the air temperature inside the greenhouse. It was dependent on different sources of energy which affect the greenhouse microclimatic conditions. The output of the model are the air temperature inside the greenhouse, relative humidity of the inside air and the soil surface temperature. The model was validated experimentally for the climatic conditions of Ismailia governorate through seven nonconsecutive days during October 2008. The data was collected under different shading conditions of the greenhouse, i.e. shading with water flow, shading only, and unshading conditions. The results of simulation model were compared with the experimental results. A good agreement was found between the measured and predicted values. The obtained results also showed that the proposed model performed well and it was adequate to simulate the microclimatic conditions.