Abstract: This dissertation,applying the model of soil layered water balance of agro-forestry,calculates the water uptake by the roots of wheat and shelterbelt,the evapo-transpiration, and the extent that the effects of shelterbelt exerted on the field soil water,then to study the evapo-transpiration of agroforestry.The results show that:(1) Water uptake byroots of the shelterbelt mostly come from the field at the jointing-filling stage of winter wheat,which is obviously indicated in 0.0H～1.5H.(2)If the field is protected by the shel-terbelt,the average evapo-transpiration is 12.3% lower than that of the open wide field.(3)The field soil water content reduces in 0.0H～0.5H and raises in 0.5H～5.0H because of the shelterbelt effect.In general,the soil water capacity at the field soil depth of 0～200 cmcan be raised by 11.2%.