Aiming at the characteristics that mulberry-soybean intercropping could alleviate the damage of saline-alkaline soil, Biolog technique was adopted to study the effects of this intercropping on the diversity of carbon-metabolic microbial community in the rhizosphere of saline-alkaline soil. Under mulberry-soybean intercropping, the average well color development (AWCD) symbolizing the metabolic activity of soil microbes was obviously higher, as compared with that under mulberry or soybean monocropping, being the lowest under mulberry monocropping. The McIntosh index was also higher under intercropping than under monocropping, but the Shannon index and Simpson index had less difference between intercropping and monocropping, indicating that intercropping changed the composition and enhanced the diversity of the microbial community in the rhizosphere of saline-alkaline soil. Principal component analysis (PCA) showed that the carbon source utilization mode of the soil microbial community differed between intercropping and monocropping, and the main carbon sources were carbohydrate, carboxylic acid, and polymers. Soil pH and salinity were the main factors limiting the diversity of the microbial community in saline-alkaline soil, and intercropping could effectively decrease the soil pH and salinity and promote the improvement of soil microbial community diversity.