The experiment studied the effects of different years of continuous cropping on soil bacterial community structure and diversity in facility cucumber field under straw returning，so as to explore the microbial mechanism of soil restoration of continuous cropping soil.Five different rhizosphere soil treatments were sampled，including continuous corn-returning for 1，3，5，10 and 15 years.High-throughput sequencing and quantitative PCR were used to analyze the characteristics of soil bacterial community composition，community diversity and potential functions，as well as the change patterns.Continuous cropping under straw returning increased the contents of organic matter，total nitrogen，reduced alkali-hydrolyzale nitrogen.Soil pH decreased first and then increased.With the increase of cropping years，electrical conductivity increased.The activities of alkaline phosphatase and sucrase increased.The gene copy numbers of soil bacteria in different treatments ranged from 2.98×109 to 7.81×109 copies·g-1 soil.It was found that continuous cropping under straw returning increased the abundance of soil bacteria.The relative abundance of Actinobacteria，Proteobacteria，Chloroflexi and Firmicutes was stable at more than 75%.With the increase of cropping years，the relative abundance of Chlorocurvula and Acidobacteria increased，while the relative abundance of Firmicutes decreased.Diversity analysis showed that there were no significant changes in bacteria diversity(P>0.05).The principal coordinate analysis showed that the differences in bacterial community structure among treatments were highly significant(P<0.01)，which indicated continuous cropping could affect the bacterial community structure.FAPROTAX function prediction showed that chemoheterotrophy and aerobic_chemoheterotrophy were the main types.The co-occurrence network analysis showed that the complexity and stability of the genus level enhanced after continuous cropping.Redundancy analysis showed that total phosphorus had greatest effect on the soil bacterial community structure (F=3.5，P=0.002)，explaining 21.3% of the community changes.The order of contribution was total phosphorus>alkali-hydrolyzale nitrogen>available phosphorus>pH>available potassium>electrical conductivity>total nitrogen>organic matter.The bacterial community had the greatest effect on urease(F=4.6，P=0.002)，accounting for 26.3% of the community changes.The order of effect on enzyme activity was urease>catalase>sucrase>polyphenol oxidase>alkaline phosphatase.The positive effect of straw return on stabilizing soil bacterial diversity in continuous cropping and the beneficial effect in mitigating continuous cropping barriers in facility crops were confirmed.Total phosphorus was the main effective environmental factor influencing the changes of soil bacterial community structure.The change of bacterial community had the greatest effect on soil urease activity.