Xiangzayou763 was used as material to study the effects on rapeseed stem-leaf soluble sugar and free amino acids and rapeseed yield in different fertilizer levels(N∶P2O5∶K2O∶B：A，240∶120∶210∶1.2 kg/hm2; B, 180∶90∶157.5∶0.9 kg/hm2; C，120∶60∶105∶0.6kg/hm2; D，60∶30∶52.5∶0.3 kg/hm2; E，no fertilizer)and planting density(7.5×104, 1.5×105, 2.25×105, 3.0×105, 3.75×105, 4.5×105plant/hm2). The result indicated that the content of soluble sugar in rapeseed stem was decreased with fertilizer increased and inseased with density increased; The content of free amino acids took an upward trend with increasing fertilizer. Free amino acids amounts and total amounts of soluble sugar and free amino acids had very significant positive correlations with rape grain yield, while it had a negative correlation between soluble sugar amounts and rape grain yield. Integrated study showed that the treatment of high fertilizer (N, 240 kg/hm2; P2O5, 120 kg/hm2; K2O, 210 kg/hm2;B, 0.6 kg/hm2) and the density of 2.25×105plant/ hm2 was the most conductive to rape income.