Abstract: Dynamic change of soil microbial biomass carbon, nitrogen and phosphorus in different vegetation restoration years (1, 2, 3, 4, 5, 8, 15, 24 and 31 a) and different soil layers (0-10, 10-20, 20-30 and 30- 40 cm) and its correlation with soil nutrients in Shiyang River downstream Minqin oasis were analyzed. The results showed that (1) soil microbial biomass carbon, nitrogen and phosphorus had certain relationship with total nitrogen, available potassium and available phosphorus, available phosphorus had an obvious relationship with soil microbial biomass carbon, nitrogen and phosphorus, and the correlation coefficient was higher than that of total nitrogen and available potassium; (2) in different soil layers, the soil microbial biomass had different change rules with different vegetation restoration years; (3) the amount of soil microbial biomass carbon, nitrogen and phosphorus was dramatically different in different soil layers, the soil microbial biomass decreased with the increase of the soil depth, and the difference of soil microbial biomass in different soil layers gradually reduced with the increase of vegetation restoration year.