Abstract: Field experiment was conducted to investigate the effects of sulfur application on accumulation and transportation of photoassimilation, and grain yield, protein and starch contents, using two winter wheat cultivars with different grain protein contents, i.e. Yumai 34 (high protein) and Yumai 50(low protein). The results indicated that compared with no sulfur application treatment(S0), flag leaf’s chlorophyll (Chl) content of Yumai 34 was increased within 20 days after anthesis by sulfur applications, and flag leaf’s net photosynthesis (Pn) was increased at 25 day after anthesis. Flag leaf’s chlorophyll (Chl) and net photosynthesis (Pn) of Yumai 50 in all the treatments with sulfur application were higher than control (S0) after anthesis. The dry matter and nitrogen content in vegetative organs of both cultivars before anthesis were increased by sulfur applications, and their transportation ratio (TR) and movement ratio (MR) were increased too. Finally, compared with no sulfur application treatment (S0), grain weight and grain nitrogen accumulation of single stem in sulfur application treatments were increased at maturity stage. Compared with S0, the yield components of both cultivars with the treatment of 20 kg/ha sulfur application were increased, and grain yield was significantly increased by 10.69% and 9.78%, respectively. Meanwhile, protein and starch contents were significantly increased. The effect of high rate of sulfur application (S 100 kg/ha) treatment was inferior to low rate sulfur application (S 20 kg/ha) treatment.