The experiment explored the effects of substituting organic fertilizer for inorganic fertilizer on the fertility and bacterial community structure of calcareous brown soil in northern China，six treatments were set up，including control （CK），single application of chemical fertilizer（W），70% chemical fertilizer + 30% organic fertilizer（70W+30M）， 50% chemical fertilizer + 50% organic fertilizer（50W+50M），30% chemical fertilizer + 70% organic fertilizer （30W+70M），and single application of organic fertilizer（M）. The changes in bacterial community structure were studied using IlluminaMiseq PE300 platform. the result showed that：（1）Compared with W treatment，the soil organic matter was increased by 17.06% and 22.53% in the 30W+70M and 100M treatments，and the total nitrogen content was increased by 8.75% and 10.0%，respectively. The soil total phosphorus content was increased by 7.5% in the 50W+50M treatment，and the soil available phosphorus was increased by 21.97% in the 30W+70M treatment. The application of W treatment resulted in the highest yield of rapeseed，with no significant difference compared to 30W+70M.（2）Compared with W treatment，the soil urease activity increased by 30.25% in the 30W+70M treatment，and the sucrase activity was increased by 21.04% in M treatment.（3）The relative abundance of Proteobacteria was the highest in the soil treated with W treatment（52.3%）， while the relative abundance of Gemmatimonadota was the highest in the 30W+70M treatment（21.8%）.（4）Redundancy analysis showed that total nitrogen was the most significant environmental factor affecting soil bacterial community structure. Therefore，it could be concluded that organic substitution of inorganic fertilizers improved soil physical and chemical properties，enhanced the community structure and abundance of soil bacteria，among which the 30W+70M treatment was a more effective fertilization mode.