Abstract: The mild desertification, moderate desertification, severe desertification, and extreme desertification of alpine grassland soil were selected as the research objects.The soil samples, which were collected from 0-10,10-20 cm, and 20-30 cm, respectively, were used to test the soil sucrase activity, urease activity, catalase activity, protease activity and the number of soil bacteria, actinomycetes, and fungi in these soil samples under different degrees of desertification, and did correlation analysis.In order to explore the characteristics of soil enzyme activity and microbial quantity in the alpine grassland with different degrees of desertification, based on these test results, it was analyzed that the soil enzyme activity and microbial quantity affected by desertification.The results showed that, 1) as the degree of desertification intensifies, the activities of soil sucrase and protease decreased gradually, the activity of urease increased first and then decreased, and the activity of catalase first decreased and then increased.2) The number of bacteria, actinomycetes, and fungi showed a decreasing trend with the increasing of desertification.3) Under the same degree of desertification, soil enzyme activity and microbial quantity decreased gradually with the increasing of the soil depth.4) Urease activity, catalase activity, and protease activity had a certain correlation with bacteria and actinomycetes, but there was no obvious correlation with fungi.It could be seen that the severe desertification of the alpine grassland lead to a decrease in soil enzyme activity and a sharp decline in the number of microorganisms, soil quality decline.