Field experiments were carried out to investigate the effects of nitrogen and phosphorus application rate on rape growth in Taihu Lake region. The results showed that nitrogen and phosphate fertilization could increase rapeseed yield and there was no significant reduction when the conventional nitrogen fertilizer application rate were reduced by 25%. The optimal treatment was N 200 kg/hm2 and P2O5 110 kg/hm2 with N efficiency 60% and P efficiency 42%. The maximal fertilizer efficiency was 68% for nitrogen and 45% for phosphorus. The correlation coefficient was above 0.95 between the yield and biomass with significant quadratic curve correlation in nutritional growth stage but linear correlation in reproductive stage. Phosphate fertilization could increase the content of P-Olsen in soil. These results can provide theoretic instruction for practical field management in rape cultivation.