Abstract: 【Objective】 The purpose of this study is to screen the endophytic bacteria with antibacterial effect from the Korla pear tree with a view to using the endophytic biocontrol agent to keep the pear fresh after harvesting. 【Method】 The pathogen of postharvest black spot of fragrant pear and endophytic bacteria were isolated by tissue separation method and then the isolated strains were sequenced by ITS gene and 16S rRNA gene.Also, the plate confrontation method was used to screen the antagonistic bacteria against Alternatia alternata XL₂ from the screened endophytic bacteria, and bacteriostasis experiments of the antagonistic bacteria were conducted in vitro fruits. 【Result】 The pathogen of postharvest diseases of Korla pear Alternatia alternata XL₂ was obtained in this experiment, and 16 strains of endophytic bacteria were isolated from the leaves and branches of pear trees, among which 8 strains had inhibitory effect on Alternatia alternata XL₂.They were 1 Bacillus paralicheniformis, 5 Bacillus velezensis, 1 Bacillus siamensis and 1 Bacillus tequilensis.Among them, Bacillus velezensis NY₂, NY₇ and NY₅ had the best antibacterial effect in the Oxford cup experiment, and the diameter of antibacterial zone was more than 20 mm.In the bacteriostatic experiment of Korla pear, NY₂ and NY₁₅ had the best bacteriostatic effect, and the bacteriostatic rate was more than 30%.In the bacteriostatic test in vitro fruits, the bacteriostatic rate of NY₂ reached more than 80% in the fourth day after inoculation, and the bacteriostatic effect of NY₁₁ was more stable than others. 【Conclusion】 In this experiment, 2 strains of endophytic bacteria with antibacterial effect are screened.