【Objective】 Soil salinization restricts the improvement of nutrient utilization efficiency and productivity enhancement. Studying the dynamics of soil nutrient changes and microbial feedback under saline stress can provide a scientific basis for nutrient management in salt-affected soils. 【Method】 Soils with salinity ranging from <3 g·kg^-1(S₁), 3～10 g·kg^-1(S₂), and >10 g·kg^-1(S₃) of typical soil salinization areas in China were collected. By analyzing the differences in carbon, nitrogen, and phosphorus contents, microbial biomass, extracellular enzyme activity and their ecological stoichiometric ratios, this study aimed to clarify the changing trend of soil nutrients and microbial metabolism limitation characteristics under different salinity barriers. 【Result】 The results of the study showed that: (1) Organic carbon, total nitrogen, total phosphorus, alkaline dissolved nitrogen, and available phosphorus contents of the salt-affected soils all decreased. According to the nutrient grading standards of the Second National Soil Census, the organic carbon, total nitrogen, and alkaline dissolved nitrogen of S₃ all dropped to the fifth level (deficiency), while soil phosphorus and potassium pools were all relatively sufficient. (2) The ratio of extracellular carbon-acquiring enzyme activity to extracellular nitrogen-acquiring enzyme activity (Enzyme C/N), the ratio of extracellular carbon-acquiring enzyme activity to extracellular phosphorus-acquiring enzyme activity (Enzyme C/P) and the ratio of extracellular nitrogen-acquiring enzyme activity to extracellular phosphorus-acquiring enzyme activity (Enzyme N/P) of different salt-affected soils all deviated from 1: 1 to different degrees. Also, the results of vector characteristics of extracellular enzyme stoichiometry showed that microbial carbon limitation and microbial nitrogen limitation in S₃ were significantly higher than those in S₁ and S₂. This phenomenon indicates that increased salinization caused soil elements and microbial metabolic activity to gravitate towards carbon and nitrogen resource limitation. (3) The salt content (TS), Na⁺, K⁺, exchangeable sodium percentage (ESP), Cl^-and annual average evaporation-precipitation ratio(MAV/MAP)were the key constraints on changes in the carbon, nitrogen, and phosphorus stoichiometric ratios of soil nutrients, microbial biomass, and extracellular enzyme activities in salt-affected soils. The results of the random forest model showed that Cl^-, TS, and MAV/MAP were the main drivers of microbial relative carbon limitation. TS, ESP, sodium adsorption ratio(SAR), Cl^-, Na⁺ and MAV/MAP were the main drivers of microbial relative nitrogen limitation. 【Conclusion】 In summary, salinity barriers are more likely to lead to carbon and nitrogen limitation in arable soils than the relative abundance of phosphorus and potassium nutrient pools, and the degree of limitation increases with the strengthening of salinity barriers. Therefore, there is an urgent need to put forward methods of organic regulation and efficient carbon and nitrogen management for salt-affected arable soils.