Abstract: 【Objective】 To explore the effects of growth-promoting bacteria in the rhizosphere of Hami melons and their bio-organic fertilizers on the structure of soil microbial communities，and evaluate their roles in increasing the yield of Hami melons and maintaining soil health，which could provide theoretical basis for the development and utilization of bio-organic fertilizers. 【Method】 The tested strains were Trichoderma citrinoviride W2 strain and Trichoderma longibrachiatum W4 strain. The W2 strain and the W4 strain were fermented separately or in combination with solid substrates to prepare bio-organic fertilizer. Five treatments were set up，namely chemical fertilizer（control，CK），common organic fertilizer（COF），Trichoderma citrinoviride bio-organic fertilizer（W2），Trichoderma longibrachiatum bio-organic ferti-lizer（W4），and compound bio-organic fertilizer（W24）. The seedlings of Dumi No. 5 variety Hami melon were used as the experimental materials for field experiments，with an application rate of 13200 kg/ha. The growth and development indicators of Hami melons and the physical and chemical properties of soil were determined，and the changes in soil microbial community structure were analyzed based on Illumina Miseq high-throughput sequencing technology. 【Result】 The field experiment revealed that the transverse diameter，longitudinal diameter and weight of Hami melon fruits treated with W24 were the highest，and there was significant difference from CK（P<0.05，the same below）. The stem length，root length and the number of leaves of Hami melons treated with W24 were significantly higher than those treated with CK. The fresh weight and dry weight of the aboveground，as well as the fresh weight and dry weight of the root system of Hami melons treated with W2，W4 and W24 were all higher than those treated with CK and COF. Among them，the difference between W24 treatment and CK was significant. During the vine extension and harvest periods of Hami melons， compared with CK，W24 treatment could increase the contents of available phosphorus，available potassium，alkaline hydrolyzable nitrogen and organic matter in the soil，and reduce the soil pH. Bio-organic fertilizer also had obvious impact on the structure of soil microbial communities. Compared with CK，W24 treatment could increase the Alpha diversity index of soil bacterial and fungal communities，increase the relative abundance of Firmicutes，Actinobacteria and Chloroflexi in the soil bacterial community，increase the relative abundance of Ascomycota，Basidiomycota and Zygomycota in the soil fungal community. The results of correlation analysis indicated that Firmicutes was extremely significantly and positively correlated with the content of soil organic matter（P<0.01，the same below），while the Zygomycota was extremely significantly and positively correlated with the contents of soil alkaline hydrolyzed nitrogen，available potassium， available phosphorus and the weight of Hami melon fruits. 【Conclusion】 The compound bio-organic fertilizer containing Trichoderma citrinoviride and Trichoderma longibrachiatum can greatly promote the growth and development of Hami melons，enhance soil fertility，increase the diversity of soil microbial communities and promote the growth of beneficial bacteria. It has application potential in maintaining soil health and increasing the yield of Hami melons.