This study adopted the method of space instead of time series to explore the coupling coordination relationship between soil physicochemical properties and microbial biomass of Leucaena leucocephala in six succession ages in Xiangjiaba engineering disturbance area by analysis of variance, correlation analysis and partial least squares path model. The results showed that: 1) Soil water content, nutrient level and microbial biomass were all the highest in native grassland community (A1, 0 year), and were decreased significantly in the grass-shrub stage after the invasion of Leucaena leucocephala. When Leucaena leucocephala became shrubbery (A3, 2 years), soil water content, organic carbon, total nitrogen, total phosphorus, microbial carbon, and microbial nitrogen contents decreased to 51.2%, 33.9%, 31.6%, 27.1%, 72.8% and 61.5% of A1 community, respectively. Soil pH was increased to 8.16, making soil more alkaline. 2)Soil microbial carbon contents were significantly correlated with soil water content (P<0.05). The microbial biomass carbon-nitrogen radio was also significantly correlated with soil pH. The interaction among soil water content, nutrient level and microbial biomass was significant, so high soil water content was conducive to the existence and transformation of soil nutrients and microbial biomass. 3)The structure of the original sample was stable, so the coordination degree was higher (0.716 2). After the invasion of Leucaena leucocephala, the coordination degree was decreased with the age increase of Leucaena leucocephala, and decreased to the lowest (0.501 2) in A4 (3-4 years). In the arbor stage, soil nutrients and microbial biomass were increased slowly and tended to be stable, and the coordination degree was increased slowly and finally stabilized in the pure plantation of Leucaena leucocephala. Therefore, for Leucaena leucocephala plantation in different succession ages, different regulatory measures should be taken according to soil habitat conditions at different stages of restoration. In the selection of species for vegetation restoration, attention should be paid to the combination of grass-shrub in order to promote the healthy development of soil and the entire ecosystem.