The of daily variation and the seasonal variation of transpiration intensity of different trees are analyzed. The regression model that explains the influence of illumination, air temperature, relative humidity, wind velocity and ground temperature on trees transpiration is set up. The results indicated that the water consumption for trees transpiration in the growth season of larch and locust is 107.9%～119.5% of the same term rainfall, the imported precipitation of the soil can not satisfy the needs of the consumption of the arbor, and hold up their normal growth. The water consumption for the transpiration of Caragana Korshinskii and Hippophae rhemnoides is 61.66%～66.1% of rainfall in the same tern, the imported precipitation of the soil can satisfy the needs of the consumption of shrub forest land.