The aim of the current study was to examine the dynamic changes of soil physicochemical properties and microbial quantities, and to provide theoretical basis for the improvement and restoration of the degraded grassland in Gannan alpine meadow. The soil samples were collected from light degradation (LD), moderate degradation (MD), extreme degradation (ED) and control grassland (CK) in May, July and October, 2017, to investigate the physiochemical characteristics and the microbial quantities. The results showed that the soil water content of CK was significantly lower than that of the degraded grassland in May and July, while significantly higher than that of the degraded grassland in October. With the aggravation of degradation degree, soil pH value gradually increased, while the content of organic carbon, total nitrogen and total phosphorus gradually decreased. The number of soil bacteria was more sensitive to grassland degradation, followed by actinomycetes and fungi. The soil microbial quantities of CK and LD decreased more obviously with the increasing of soil layer depth. Redundancy analysis and the Monte Carlo permutation test showed that the environmental factors affecting soil microbial quantities were different in each month. Soil microbial quantities were significantly affected by total phosphorus and soil water content in May, while other factors except soil pH had significant effects in July. Except soil pH value and C/N, vegetation coverage, aboveground and underground biomass and other environmental factors had significant effects in October. All of the above results revealed that the responses of soil physicochemical characteristics and soil microbial quantities to grassland degradation had have seasonal variation in Gannan alpine meadow, the influencing factors and weights in different periods also needed to be paid attention to in grassland management.