The northern agro-pastoral zone is an important ecological barrier in China,but the degradation of grasslands in the region has intensified as a result of global changes and intensified human activities,and there is an urgent need for green and sustainable soil restoration measures. Microorganisms and organic fertilisers have shown a positive role in agricultural soil improvement. However,there are fewer studies on the application of microbial compound inoculants in the restoration of degraded grasslands in ecologically fragile areas. Microbial compound inoculants are able to play an important potential in improving soil structure,enhancing soil fertility,and promoting plant growth due to the synergistic effect of multiple strains,which is expected to be a low-cost and high-efficiency strategy for grassland restoration. In this study,three beneficial microorganisms,namely Bacillus subtilis,Azotobacter salinestris,and Claroideoglomus lamellosum,were selected and applied in a pot experiments,either individually or in combination with organic fertilizers,to investigate the effects on the physicochemical properties of the degraded grassland soil,microbial factors and plant biomass,and to compute the comprehensive indexes of soil quality scores by using the affiliation function in combination with the factor analysis method,to compare the soil quality improvement effects of the different microbial additives. The results showed that organic fertiliser combined with beneficial microorganisms could improve the soil quality. The results showed that the combination of organic fertiliser with beneficial microorganisms significantly increased the effectiveness of soil nutrients and improved soil quality. Compared with the application of organic fertiliser alone,the addition of microbial inoculants significantly promoted plant growth and nutrient uptake,and the best effect was achieved by the mixing of three microorganisms. At the same time,it was found that there were synergistic effects among different combinations of microbial composites,which enhanced the functional performance of microorganisms in the soil,such as increasing soil enzyme activity,promoting soil nutrient cycling,and enhancing the microbial biomass,which ultimately enhanced the nutrient uptake and growth of plants. This study provides a feasible path and theoretical basis for microbial-based grassland ecological restoration technology,and provides scientific perspectives and practical guidance for improving the function of degraded grassland ecosystems,maintaining soil health and guaranteeing the sustainable development of grasslands.