In order to clarify the responses of soil enzyme activities to changing precipitation regimes in desert steppe, we carried out this study based on field experiments (started in 2014) of different gradient changes of precipitation (50% reduction, 30% reduction, control, 30% increase and 50% increase) in a desert steppe in Ningxia. The sampling time was from May to July in 2016. The activities of soil enzymes were studied after two years of treatments, their relationships with plant biomass, microbial biomass C∶N∶P ecological stoichiometry, and soil physicochemical properties were analyzed too. The results showed that: (1) compared with natural precipitation, the 30% reduction in precipitation did not significantly affect the three soil enzyme activities (P > 0.05), while the 50% reduction in precipitation significantly decreased the invertase activity (P < 0.05). Increased precipitation significantly increased the activities of invertase and phosphatase (P < 0.05), whereas no significant effect on urease activity (^P > 0.05). (2) Decreased precipitation had little effect on plant biomass (especially 30% reduction), whereas it reduced microbial biomass C, N, P and increased microbial biomass C∶N and C∶P to varying degrees. Increased precipitation increased plant biomass and microbial biomass C, N, P to certain degrees. (3) Mostly, the activities of soil invertase and phosphatase increased with the increasing plant and microbial biomass. The soil factors that had significant influences on soil enzyme activities included water content, NO₃^-N, NH₄⁺N, C∶P, organic C, total N, C∶N, and pH (P < 0.05). The results of this study suggest that shortterm reduction in precipitation (especially 30% reduction) would have little influences on soil enzyme activities in the studied desert steppe; increasing precipitation could promote plant growth and microbial activity, and then improve the activity of invertase. However, with the increase of plant biomass accumulation, more organic C is sequestrated in soils, the activity of phosphatase in soils increased correspondingly and promoted the mineralization of organic P, resulted in the aggravation of P limitation of microbes.