Abstract: Field experiments were conducted to investigate effects of different planting densities and fertilizer application levels on N, P, K (nitrogen, phosphorus, potassium) uptake and seed yield of rapeseed variety Xiangzayou 763.The results showed that, yield of high fertilizer application treatment were significantly higher than that in the low fertilizer application treatment under the same planting density, and there were significant or highly significant differences in seed yield among the 4 fertilizer application treatments. Seed yield in 2 treatments (higher fertilizer application level with lower planting density treatment, lower fertilizer application level with higher planting density treatment) were relatively higher. The highest yield (N was 180 kg/hm2，P was 90 kg/hm2, K was 158 kg/hm2 and the planting density was 75 000 plants /hm2) was 2 696.15 kg/hm2 among the 24 treatments. Higher fertilizer application treatments had higher NPK accumulation, which was consistent to the seed yield, and there was highly significant correlation between yield and NPK accumulation. The contents of N and P during flowering and harvesting stages, which were much higher than those during the wintering stage, increased first and then decreased, but the change was not obvious. The K content showed less change.