Abstract: To explore the microbiological response to incorporation of Chinese milk vetch and chemical fertilizers in paddy soils, a 7-year field experiment was used to investigate the effects of different fertilization regimes on the number of microorganisms, microbial biomass carbon (SMBC) and nitrogen (SMBN) contents, soil microbial quotient (qMB) and rice yield. The results showed that: (1) Compared to the control (CK), long-term use of milk vetch significantly increased soil microorganisms by 58.1%-86.9%, especially the number of bacteria (77.9%-112.8%). The highest soil microorganism and bacteria numbers were found in the 70% mineral fertilizer combined with 22500 kg/ha milk vetch treatment with value of 288.26×10⁴ and 263.95×10⁴ CFU/g, respectively. (2) Application of milk vetch can effectively increase the content of microbial biomass. Compared with CK, 70% of normal mineral fertilizer application combined with milk vetch increased SMBC, SMBN, qMB by 102.8%-113.9%, 172.5%-185.2% and 69.5%-84.7% respectively. Compared with 100% mineral fertilizer treatment, 70% mineral fertilizer application combined with milk vetch increased SMBC, SMBN, qMB by 27.7%-34.8%, 74.1%-82.2%, 20.5%-31.3% respectively. (3) 70% mineral fertilizer application combined with milk vetch incorporation maintain or improved crop yields compared with 100% the mineral fertilizer treatment, but significantly increased crop yields compared with CK and the 70% mineral fertilizer treatment. Compared with CK, mineral fertilizer application combined with milk vetch increased crop yield by 46.2%-51.4%. It was concluded that mineral fertilizer reduction of 30% combined with milk vetch can increase the rice yield in Anhui double cropping areas along the Yangtze River. In this experiment, the application of 22500 kg/ha milk vetch achieved the highest yield increase (51.44%). Application of 70% mineral fertilizer combined with milk vetch plays a significant role in increasing soil microbial biomass and soil microbial quotient, regulating soil microbial community composition as well as improving soil biological properties in paddy soil.