Abstract: The effects of nitrogen application ratios at different growing stages of wheat on grain quality and yield of interplanted strong-gluten wheat in paddy fields were studied. The field experiment was conducted in Tongshan and Ganyu (Huaibei Area, Jiangsu province) from 2004 to 2006. There were five nitrogen application ratios, namely 6∶1∶3∶0 (base:tillering:elongation:booting), 5∶1∶4∶0, 5∶1∶2∶2, 3∶3∶2∶2 and 3∶3∶1∶3 in the experiment. The cultivar was Yannong 19. The results: 1) the grain protein and wet gluten contents are increased when nitrogen fertilizer application time is defered, and nitrogen fertilizer application time has less effects on albumin and globulin contents, while has great impact on gliadin and glutenin contents; 2) Grain starch content of wheat flour is decreased when the elongation and booting N fertilizer applied amount is increased, and peak viscosity, trough viscosity, breakdown and final viscosity of flour are increased at first and then eventually dropped; 3) Dough development time and stability time are increased as the proportion of elongation and booting N fertilizer is increased; 4) Grain yield is increased as the proportion of elongation and booting N fertilizer is increased, while the yield is decreased when the ratio of elongation and booting N fertilizer is too high. In order to get high grain yield and good quality, the suitable nitrogen application ratio (base:tillering:elongation:booting) is 3∶3∶2∶2 for interplanted strong-gluten wheat in paddy fields.