Abstract: Abstract：In order to understand the effects of 40%FC、60%FC和80%FC on Glutamine Synthetase (GS) activity of flag leaves and grain and quality of winter wheat with specialized end-uses,pot experiments were carried out.The results showed that GS activity in flag leaf was Higher than in grain,he activity among three water treatments showed: In grain formation and filling, GS activity in flag leaves showed: 60%FC>80%FC>40%FC,In other stage showed that: 80%FC>60%FC>40%FC with Yumai 49. The GS activity of grain of Yumai 49 and the leaves、grain of Yumai 50 showed: 80%FC>60%FC>40%.The highest grain yield in the 80%FC treatment and 40%FC had the lowest grain yield. There was a significant correlation between GS activity of flag leaves and grain and grain yield during the middle stage of grain filling.