In order to explore the effects of exogenous organic materials on the improvement of salinized farmland in Shiyang River irrigation area, in this study, woody peat and decomposed straw were used as experimental materials, the changes of chemical properties and microbial communities of salinized farmland soil under different amounts of organic materials were analyzed through field experiment and high-throughput sequencing. The results showed that compared with the control, the addition of organic materials reduced the electrical conductivity and total amount of water-soluble salts, increased the contents of organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium and CEC, and adjusted the concentrations of base ions. The treatments of 9 000 kg/hm² woody peat + 3 000 kg/hm² decomposed straw and 13 500 kg/hm² woody peat + 4 500 kg/hm² decomposed straw had better effects. And the addition of organic materials changed the structure of bacterial community, significantly increased the relative abundances of Proteobacteria and Actinobacteriota, and decreased the relative abundance of Acidobacteria. Correlation analysis showed that Proteobacteria relative abundance was significantly positively correlated with total nitrogen content, Actinobacteriota relative abundance was significantly positively correlated with organic matter content and negatively correlated with water-soluble salt content, and Acidobacteriota relative abundance was significantly positively correlated with pH and negatively correlated with organic matter content and CEC. Based on the changes of soil chemical properties, salinity and microorganisms, the addition of woody peat (9 000-1 3500 kg/hm²) + decomposed straw ( 3 000-4 500 kg/hm²