In order to investigate the effects of different irrigation frequencies on the protein composition and grain quality(farinograph parameters and flour wet gluten content) of strong-gluten winter wheat,Jimai 20 was subjected to a series of irrigation frequencies under rain shelter conditions.The results indicated that with the increase of irrigation frequencies,the wheat flour dough development time,dough stability time,and wet gluten content increased firstly but decreased then,and they were the best when irrigated twice(W2).The contents of soluble glutenin,insoluble glutenin and total glutenin,the ratio of insoluble glutenin to total glutenin,D(4,3) and D(3,2) in the grains displayed the similar trends.The stepwise regression analysis showed that under the different irrigation frequencies,the key factor affecting dough stability time was insoluble glutenin content.