In order to reveal the response mechanism of soil nutrients and bacterial communities in tobacco fields to mulching，bare soil cultivation(CK)and mulching(MU)treatments were set up in a typical tobacco growing area in southern Guizhou，to observe soil physicochemical properties and bacterial communities，and to explore the correlation between soil enzymes，bacterial communities and environmental factors. The results showed that the soil available potassium content of mulching cultivation was significantly higher than that of bare soil cultivation at the topping stage and 30 days after the topping stage，with increases ranging from 12.77%-41.44% and 11.75%-16.33%，respectively. Sucrase activity decreased by 9.98%-26.30%，21.44%-25.74% and 6.58%-26.48% at topping，30 days after topping and end of harvesting and roasting periods，respectively，compared to bare soil cultivation. Acid phosphatase activity increased significantly(P<0.05)at the end of the harvesting and roasting period，with increases ranging from 9.06%-14.94%. The mulching cultivation mode changed the soil bacterial community structure and reduced the soil bacterial community richness. Mulching cultivation enhanced the relative abundance of Chloroflexi and Acidobacteriota by 47.85%-54.00% and 36.54%-73.94%，respectively reduced Proteobacteria and Actinobacteriota by 32.23%-32.35% and 24.10%-40.68%，respectively. The results of redundancy analysis showed that available potassium，available phosphorus and sucrase were the key factors influencing the changes in soil bacterial community structure. In conclusion，the mulching cultivation mode was conducive to improving soil fertility and ensuring balanced supply of soil nutrients to the growth of roasted tobacco in typical tobacco areas in southern Guizhou，and increased the percentage of beneficial bacteria abundance in the rhizosphere soil of roasted tobacco，but decreased the abundance of soil bacterial community in the inter-root soil. This result is a good guide for the application of roasted tobacco mulching cultivation in typical tobacco areas in southern Guizhou.