放牧是草地生态系统主要利用方式之一，对草地资源合理利用有重要影响。本文在内蒙古温带典型草原设置对照、轻度、中度、重度、极重度五个放牧梯度，通过分析地上植被、地表土壤和地下土壤微生物的变化，探讨不同放牧强度对土壤微生物群落结构的影响。结果表明：不同放牧强度对土壤微生物群落结构有影响，适宜的放牧强度可以增加土壤微生物数量、土壤酶活性、土壤微生物量碳氮利用效率。在轻度与中度放牧时，植物生物量最大，丰富度最好；细菌、放线菌和真菌数量最多；提高过氧化氢酶活性来适应环境的变化，产生最多的多酚氧化酶、脲酶、磷酸酶，来获取一定的C、N和P，环境对土壤微生物量碳氮的利用效率最高。此外，在非生长季，微生物受到温度和湿度的限制，其数量和酶活性相对较低，为生长季累积一定的养分。因此，选取轻度或中度为适宜的放牧强度，可持续利用草地资源。

Grazing is one of the main ways to use grassland ecosystems, and it has an important impact on the rational use of grassland resources. In this paper, five grazing gradients of control, mild, moderate, severe and extremely severe are set in the temperate typical steppe of Inner Mongolia. The effects of different grazing intensities on soil microbial community structure are discussed by analyzing the changes of above-ground vegetation, surface soil and underground soil microorganisms. The results showed that different grazing intensities had an effect on the microbial community structure. The suitable grazing intensity could increase the number of soil microorganisms, soil enzyme activity, and soil microbial biomass carbon and nitrogen utilization efficiency. In the light and moderate grazing, the plant biomass is the highest and the richness is the best; the number of bacteria, actinomycetes and fungi is the highest, and catalase activity is increased to adapt to changes in the environment, resulting in the most polyphenol oxidase, urease, Phosphatase, to obtain a certain amount of C, N and P, the environment of the highest utilization of soil microbial biomass carbon and nitrogen. In addition, in the non-growth season, microorganisms are limited by temperature and humidity, and their amount and enzyme activity are relatively low, accumulating certain nutrients for the growing season. Therefore, select moderate or moderate grazing intensity for sustainable use of grassland resources.