Planting density and nitrogen (N) fertilizer rate are two important factors to affect rapeseed growth and production,and suitable planting density and N fertilizer application are efficient to improve both rape growth and yield.One popular variety (Huayouza 9) was used in a field experiment in Yucheng village,Jianyang city,Sichuan province in 2015～2016.The experiment was arranged using a splitplot design with three replicates,and the main plots had three N fertilizer level (120 kg·hm-2 N1,240 kg·hm-2 N2,360 kg·hm-2 N3),while three plant densities (15×104 plants·hm-2 D1,30×104 plants·hm-2 D2,45×104 plants·hm-2 D3) were set up in subplots.The objective of this study was to evaluate effect of interaction between different fertilizer levels and density levels on growth period and process,biomass accumulation and distribution,yield and component,and the relationship among them.The results showed that the growth period of rape was delayed with the increase of N fertilizer rates.Density had no significant effect on rape growth period under the different N fertilizer rates.Plant height went up first and then down with the increase of N fertilizer,but a downward trend was observed with the increase of planting density.Furthermore,unit area root stout,leaf number,chlorophyll,dry weight of per plant and each organs,pod proportion,branch number,effective siliques were increased significantly with the increasing density and N fertilizer,and effect of fertilization was larger than density.The differences between each adjacent treatment were gradually decreasing with increased nitrogen fertilizer and density.Correlation analysis found that yield had significant positive relationship with unit area root stout,leaf number,chlorophyll,dry weight of per plant and each organs,pod proportion,branch number,effective siliques.The influence of transplanting density on yield was larger than N fertilizer,thus the less usage of N fertilizer and proper increasing density could achieve high yield.In this study,the target yield with 360 kg·hm-2 N fertilizer and 15×104 plants·hm-2 planting density could be achieved by 120 kg·hm-2 N fertilizer and 45×104 plants·hm-2 planting density,and the latter also saved 120 kg·hm-2 N fertilizer.