Abstract: The orthogonal design L₉（3~4） was used to study the effects of different N, P, and K dosages and planting densities on the yield and crude fat content of spring oilseed rape. The results showed that density has a very significant effect on the yield of rapeseed, and the yield of planting density of 6 000 plants per mu is extremely different from other density treatments, and the effect is the best. Multiple results show that the combined application of M2N1P2K3 has a better effect. Density and nitrogen fertilizer have a greater impact on rape yield, and the test results are extremely significant.