Abstract: In order to reveal the responses of bacterial community structure in coastal saline-alkali soil to the addition of different organic materials, field experiments were conducted to study the influences of the amendment of organic materials (straw, biochar and compost of cow manure) on bacterial community in coastal saline-alkali soil by high-throughput sequencing. The results show that compared with the control treatment, the contents of soil organic carbon, total nitrogen, available phosphorus and available potassium were all increased in the soil with the addition of organic materials. The α diversity analysis show that the addition of organic materials increased soil bacteria abundance and community diversity, and the highest bacterial abundance and community diversity were in the cow manure compost treatment and biochar treatments, respectively. Three months after the addition of organic materials, the dominant bacteria phyla were the same in the soil with or without organic materials, but the order and relative abundance of the dominant bacteria phyla were different obviously, especially for the top three dominant bacteria phyla. The dominant bacteria phyla in control treatment was Proteobacteria (29.23%)> Acidobacteria (22.52%)> Planctomycetes (13.62%)> Chloroflexi (9.7%). Compared with the control treatment, the soil with biochar significantly increased the relative abundance of Planctomycetes, which was 25.1%, while significantly reduced the relative abundance of Proteobacteria, which was 23.3%. The relative abundance of Chloroflexi in the soil with cow manure compost was the highest among all treatments and it was up to 10.27%, which was significantly higher than that in the soil with straw (7.55%). The relative abundance of Planctomycetes in the soil with straw was 22.86%, which was significantly higher than that of the cow manure compost treatment (13.82%) and the control treatment (13.62%). The distribution characteristics of dominant bacteria in genus level were similar to those in phyla level, that was due to the similarity of the dominant bacteria genus for different treatments, but the relative abundances were different among the different treatments. The dominant bacteria genus of the control treatment were in the order of uncultured bacterium RB41 (3.43%)=Sphingomonas (3.43%)> Lysobacter (2.47%)> Subgroup_10 (1.28%)> Pirellula (1%). The relative abundance of Sphingomonas in the soil with biochar (2.57%) and uncultured bacterium RB41 in the soil with straw (2.03%) were significantly lower than those of the other treatments; The relative abundance of Pirellula in the soil with cow manure compost and control treatment was significantly lower than that of the biochar treatment (2.11%). The differential species in soils with or without organic materials were as follows: for straw treatment, the main differential species were Proteobacteria α-Proteobacteria (Caulobacterales, Altererythrobacter, Hyphomonadaceae), Delta Proteobacteria Myxococcus (Sorangiineae_bacterium_NIC37A_2, Haliangium, 0319_6G20, Haliangiaceae, BIrii41) and γ-Proteobacteria (R7C24, CCD24); for cow manure compost treatment, the differential species were Proteobacteria α-Proteobacteria (Rhizobiales, Tagaea_marina) and Firmicutes (Halobacillus); and for control treatment, it was AKAU4049 of an uncertain class of Blastomonas. Statistical results show that there existed significant difference of microbial community structure in coastal saline-alkaline soil applied with different organic materials, moreover, the distribution of bacterial community was mainly influenced by soil pH, total organic carbon and electric conductivity.