Abstract:A field experiment was carried out to study the response of grain yield,quality characteristic,filling characteristic photosynthesis of flag leaves in 2 high quality wheat varieties to different N application levels.This experiment was designed using a split-plot design.5 levels of nitrogen fertilizers were the main plots and 2 varieties were the subplots.The applied amounts of nitrogen fertilizer were 0,75,150,225 and 300 kg/ha,respectively;and the varieties were strong gluten variety Linyou 145 and middle gluten variety Linyou 2018. The results showed that spike numbers,kernels per spike,filled-grain spike and yield of wheat were increased,but 1000-kernel weight were decreased by N fertilization.Spike numbers made the largest contribution to yield.N fertilization decreased average grain filling rate,prolonged filling period,improved chlorophyll and net photosynthesis rate of flag leaves.Chlorophyll and net photosynthesis rate of flag leaves had significantly positive correlation to yield and grain weight per spike,and negative correlation to 1000-kerenel weight.N fertilization improved nutritive quality and processing quality of winter wheat and increased all protein constituents.Base on effects of N fertilization on yield and quality of these two wheat cultivars,we could conclude that nitrogen fertilization pronouncedly affected grains per spike,productive spikes and yield,and inherited characteristics were the determinate factors on 1000knerel weight and winter wheat quality.