To investigate the effects of different grazing intensities on soil enzyme activities in a Stipa breviflora desert steppe and the driving factors， this study was based on a Stipa breviflora desert steppe and established four grazing intensity levels： no grazing （CK）， light grazing （LG）， moderate grazing （MG）， and heavy grazing （HG）. The effects of different grazing intensities on the activities of β-D-cellobiohydrolase， β-1，4-N-acetylglucosaminidase， and alkaline phosphatase were analyzed， along with species richness， aboveground net primary productivity （ANPP）， and soil pH， saturated water content， bulk density， organic carbon， available nitrogen， and available phosphorus. The results showed that with the increase of grazing intensity， the three soil enzyme activities， species richness， aboveground net primary productivity， soil organic carbon， available nitrogen， and available phosphorus all significantly decreased （P<0.05）， whereas soil bulk density was significantly increased. The Random Forest model indicated that available nitrogen and available phosphorus were the primary drivers regulating soil enzyme activities. Grazing suppresses soil enzyme activities primarily by decreasing available nutrients. This study provides a theoretical basis for the conservation and ecological restoration of desert steppes. In grassland management and utilization， measures such as controlling stocking rates and implementing seasonal grazing exclusion can be adopted.

Grazing intensity  /  Desert steppe  /  Soil enzyme activities  /  Species richness