对甘肃民勤连古城国家级自然保护区内霸王〔Zygophyllum xanthoxylum （Bunge） Maxim.〕、红砂〔Reaumuria songarica （Pall.） Maxim.〕、猫头刺（Oxytropis aciphylla Ledeb.）、针茅（Stipa capillata Linn.）群落0~20、20~40和40~60 cm土层土壤的理化性质和酶活性进行比较，并对土壤理化指标与土壤酶活性的关系进行分析。结果表明：总体上，4种植物群落土壤中，红砂群落的土壤总有机碳、全氮、速效磷和速效钾含量及蔗糖酶活性最高，针茅群落的土壤全磷含量最高，猫头刺群落的土壤全钾含量最高；霸王群落的土壤脲酶、淀粉酶、纤维素酶和碱性磷酸酶活性最强。总体来看，4种植物群落土壤理化指标均随着土壤深度增加而降低，4种植物群落的土壤脲酶、过氧化氢酶、蔗糖酶和碱性磷酸酶活性以及霸王、红砂和针茅群落的土壤淀粉酶活性也随着土壤深度增加而减弱。Pearson相关性分析结果表明土壤理化指标与土壤酶活性多呈显著（P<0.05）或极显著（P<0.01）正相关。冗余分析结果显示：第1和第2轴分别能够解释民勤荒漠区植物群落土壤理化性质与土壤酶活性关系的61.01%和18.63%，并且，土壤总有机碳含量、速效钾含量、pH值和含水量对土壤酶活性的影响较大；蒙特卡罗检验结果显示土壤铵态氮含量、pH值、总有机碳含量和含水量对土壤酶活性影响的贡献率分别为31.6%、12.7%、11.8%和11.6%，且影响均达到显著水平。综上所述，甘肃民勤荒漠区4种植物群落总体表现为红砂群落的土壤理化性质最好，霸王群落的土壤酶活性最强，并且，土壤越深，指标数值越小。土壤总有机碳含量、pH值和含水量对该区域4种植物群落土壤酶活性的影响较大。

 The soil physicochemical properties and enzyme activities in soil layers of 0-20, 20-40, and 40-60 cm within communities of Zygophyllum xanthoxylum （Bunge） Maxim., Reaumuria songarica （Pall.） Maxim., Oxytropis aciphylla Ledeb., and Stipa capillata Linn. in Minqin Liangucheng National Nature Reserve of Gansu Province were compared, and the relationships between soil physicochemical indexes and soil enzyme activities were analyzed. The results show that, in general,  among the soils of the four plant communities, the contents of total organic carbon, total nitrogen, available phosphorus, and available potassium, as well as sucrase  activity in soil of R. songarica community are the highest, the total phosphorus content in soil of S. capillata community is the highest, while the total potassium content in soil of O. aciphylla community is the highest; the activities of urease, amylase, cellulase, and alkaline phosphatase in soil of Z. xanthoxylum community are the strongest. Overall, the soil physicochemical indexes  of the four plant communities decrease with the increase of soil depth, the activities of urease, catalase, sucrase, and alkaline phosphatase in soils of the four plant communities, as well as the amylase activity in soils of Z. xanthoxylum, R. songarica, and S. capillata communities also decrease with the increase of soil depth. The result of Pearson correlation analysis indicates that there are  significant （P<0.05） or extremely significant （P<0.01） positive correlations between most soil physicochemical indexes and soil enzyme activities. The result of redundancy analysis reveals that the first and second axes can explain 61.01% and 18.63% of the relationships between soil physicochemical properties and soil enzyme activities of plant communities in Minqin desert region, respectively. Moreover, the effects of soil total organic carbon content, available potassium content, pH value, and water content on soil enzyme activities are relatively great. The result of Monte Carlo test indicates that the contribution rates of effects of soil ammonium nitrogen content, pH value, total organic carbon content, and water content on soil enzyme activities are 31.6%, 12.7%, 11.8%, and 11.6%, respectively, and all effects reach significant level. In summary, the soil physicochemical properties of R. songarica community are the best, and the soil enzyme activities of Z. xanthoxylum community are the strongest among the four plant communities of Minqin desert region of Gansu Province. Furthermore, the deeper the soil, the smaller the index value. Soil total organic carbon content, pH value, and water content have relatively great influence on soil enzyme activities of the four plant communities in this region.