The balancing of plant functional traits combination is an important mechanism for plants to adapt to the soil environment, and it also affects rhizosphere processes and ecosystem functions by regulating rhizosphere effects (RE). The typical desert steppe in Yanchi County of Ningxia was selected as the study area. The effects of different soils on the functional traits and RE of Agropyron mongolicum and their relationships were explored through comparing the functional traits and REs of A. mongolicum in sierozem soil, dark loessial soil and aeolian soil. Results highlighted that:(1) there were significant differences in the physicochemical properties of the rhizosphere and non-rhizosphere soils in different soil types, and the changes of physicochemical properties of rhizosphere soil were related to the properties of non-rhizosphere soil. (2) There were differences in the RE in different soils, and the RE size of different factors varied with soil. The overall performance of RE was the largest in aeolian soil and the smallest in sierozem soil. Soil physicochemical properties were the main factors affecting the RE of A. mongolicum, which could explain 69.5% of the variation of RE. (3) Soil physicochemical properties were closely related to the functional traits of A. mongolicum, which had the greatest impact on root length and root-shoot ratio. The functional traits of A. mongolicum were closely related to the RE size, and root length and root-shoot ratio were the main factors affecting RE. This study indicated that the A. mongolicum improved soil properties and soil quality through RE, which was regulated by soil physicochemical properties and plant functional traits together.