Field plot experiment was carried out on Xiangzayou763 to study the effects of different fertilizer application levels (N∶P2O5∶K2O∶B，treatment A，240∶120∶210∶1.2 kg/hm2；treatment B，180∶90∶157.5∶0.9 kg/hm2； treatment C，120∶60∶105∶0.6 kg/hm2; treatment D：60∶30∶52.5∶0.3 kg/hm2; treatment E, no fertilizer) and different planting densities (7.5×104, 1.5×105, 2.25×105, 3.0×105, 3.75×105, 4.5×105 plant/hm2) on oil content, protein content, thioglycoside content and erucic acid content in seeds. The results showed that oil content and protein content in seeds were greatly influenced by fertilizer application levels but less influenced by planting densities. Oil content of treatment C and D were much higher, protein content was increased with fertilizer application level increasing. Effects of fertilizer application level on oil content and protein content were higher than that of planting densities and the same trend was observed in seeds yield changes. The highest oil content and protein content were shown in fertilizer application treatment A with 2.25×105 plant/hm2 planting density. There was no regular change of thioglycoside content and erucic acid content in seeds under different fertilizer application levels and planting densities.