[Objective] With trough-cultured experiment,the effects of different irrigation quantity on the chlorophyll fluorescence of winter wheat flag leaves and the grain yield were studied.[Method]Research was carried out at Experiment Station of Shandong Agriculture University by different irrigation quantity.A winter wheat cultivar with high grain yield and strong gluten viz.Jimai20 was selected in the study.The chlorophyll fluorescence of flag leaf after anthesis was measured.[Result] With the increase of irrig...