【Objective】Nitrogen (N) and sulfur (S) are nutrient elements essential to winter wheat in growth and development. The purpose of this article was to determine the effects of nitrogen and sulfur and their interaction on flag leaf senescence, photosynthetic rate after anthesis, accumulation and distribution of dry matter, grain yield and nitrogen use efficiency (NUE) of winter wheat. 【Method】A field experiment, designed to have two cultivars (Yannong 19 and Wennong 6) of wheat, three levels of N application rate, that is 0 (N0), 120 (N120) and 240 kg N hm^-2 (N240) and four levels of S application rate, that is 0 (S0), 20 (S20), 40 (S40) and 60 kg S hm^-2 (S60), was carried out. 【Result】Results show that Wennong 6 was higher than Yannong 19 in all the four following indices, that is, superoxide dismutase (SOD) activity in flag leaf, photosynthetic rate (Pn) in flag leaf, yield, and NUE. Application of an appropriate rate of S in addition to the application of a certain amount of nitrogen significantly increased the activity of SOD, the concentration of soluble protein, Pn and dry matter accumulation in flag leaf after anthesis, and hence nitrogen accumulation in the shoot and grain yield in both cultivars of wheat. In the plots applied with 120 kg hm^-2 of N and over 40 kg hm^-2 of S or with 240 kg hm^-2 of N and over 20 kg hm^-2 of S, nitrogen accumulation in the shoot kept on rising, but no more positive effects on antioxidant ability and photosynthetic assimilation capacity of the flag leaf and grain yield were observed in Wennong 6, while SOD activity, soluble protein concentration and Pn in the flag leaf, nitrogen accumulation in the shoot and grain yield all declined in Yannong19. 【Conclusion】In the plots the same in N application rate, NUE of the two cultivars generally decreased with increasing sulfur rate. In the plots where soil available sulfur in the 0~20 cm soil layer was in the range of 38.9~42.1 mg kg^-1, application of an appropriate amount of N and S could delay senescence of the flag leaves was delayed, thus increasing photosynthetic assimilation capacity of the flag leaf and grain yield in both wheat varieties, but the two varieties differed in response to application of relatively high rates of N and S. The one, higher in NUE, still performed quite well in photosynthetic assimilation and yield, while the one, lower in NUE, was not so good in adaptability to a high application rate of N or S and tended to start senescence earlier at the late stage, thus affecting its yield and NUE.