Abstract: Aiming to understand the mechanism of the influence of continuous subsoiling on the bacterial community structure,we conducted a field experiment with 10 treatments in 2016-2018,including three subsoiling years(1 a,2 a,3 a),three subsoiling depths(25 cm,35 cm,45 cm) and a control(conventional tillage).Then High-Throughput Sequencing technology was used in analyzing the bacterial community characteristics of rhizosphere soil in 0-20 cm soil layer.The results showed that the soil bacterial community structure was significantly different with subsoiling years.The relative abundances of Chloroflexi,Gemmatimonadetes,Verrucomicrobia and Nitrospirae in 2018 increased significantly by 66.4%-79.4%,31.7%-62.1%,13.4%-50.9% and 19.6%-74.5%,respectively compared with those in 2017; while those of Bacteroidetes,Firmicutes,Thaumarchaeota and Cyanobacteria significantly declined.The indexes of Shannon,Chao1 and ACE in 2018 decreased significantly by 0.16%-2.07%,0.9%-5.19% and 0.17%-5.86%,respectively compared with those of CK.Under the same subsoiling depth,the diversity and richness of soil bacterial community in 2 a subsoiling were higher than those in 1 a subsoiling.The relative abundances in 45 cm subsoiling increased by 0.37-3.76%,0.07%-1.63% and 0.41-0.48%,respectively compared with that in 35 cm subsoiling,25 cm subsoiling and CK.With the increase in subsoiling years,QS treatment showed an optimal effect.Compared with conventional tillage,subsoiling increased the relative abundance of Proteobacteria,Gemmatimonadetes,and reduced the relative abundance of Actinobacteria and Nitrospirae.Subsoiling increased the relative abundance of genus Lysobacter,Arenimonas,Sphingomonas,but reduced the relative abundance of Streptomyces,Lentzea,Nocardioides. Soil bacterial abundance and diversity was significantly positively correlated with soil temperature,but negatively correlated with soil meteorological ratio.Simpson index was significantly negatively correlated with soil EC.The soil bacterial community was greatly affected by soil temperature,pH and generalized soil structure index(GSSI).The results contribute the understanding of the material and energy cycle mechanism of farmland ecosystem in Mollisols region of China from the microbial perspective,and provide the basis for enhancing sustainable production in the Mollisols region.