Abstract: The regulation of nitrogen nutrition on photosynthetic characteristics of winter wheat were studied under dryland condition. The results showed that soil water and nitrogen nutrition can markable improved the photosynthetic characteristics of winter wheat and the regulatre capability of nitrogen nutrition was influenced by soil water status. The effects of nitrogen nutrition on wheat gas exchange parameters and the limited factors to photosynthesis and canopy structure parameters were not identical under different soil water status, such as, under soil drought, photosynthetic rate decrease mainly resulted from mesophyll factor, at the same time, nitrogen nutrition can intensity the inhibition of the activities of photosynthetic apparatus. According to the soil water status, enriching the nitrogen can benefit to fully coordinate the relationship between crop and environment, and can maintain the high level of photosynthesys, to increase the soil water use efficiency and benefit of nitrogen nutrition, and so to get high crop yield.