Water transfer among atmosphere, vegetation, and soil ecosystems is very important in hydrology and ecology; However, there is very few study on this aspect for high land. Based on the experiments and climatic data of Lhasa Plateau Ecosystem Research Station, this paper used SHAW model to investigate the mechanism and characteristic of water transfer in Lhasa river valley on the Tibetan Plateau. The data from May to Oct. in 2004 were used to calibrate the parameters of SHAW model. Then, the calibrated parameters were used to validate the model. Finally, the model was evaluated by estimating soil moisture using the data from Oct. 2004 to Oct.2005. Seasonal variations of evaporation, transpiration, soil water content, root extraction and deep percolation during the whole winter wheat growth period of 2004-2005 were analyzed. Major results are reported as follows: ①Shooting-Grain filling is the key water consumed stage during the course of winter wheat growth. Water transfer mainly occurred between soil and roots. ②The total water-consumption of winter wheat is estimated to be 826 mm, it is about 1.7-1.9 times more than those reported in North China Plain. Hereinto, soil evaporation accounts for 37.5%.③ The roots of winter wheat in this region mainly extract water from 10 to 40cm soil depth, only when 10-40cm soil water is deficiency, winter wheat tends to extract water from deeper soil water (below 40cm).④During the course of winter wheat growth, total water seepage accounts for 50% of the total irrigation. In particular, two times irrigation in seed-Reviving stage, about 72% irrigation seeped down to 70cm soil. At the end, this paper also discussed the prospective of the suitable irrigation scheduling based on the results of this research on water transfer character.