Artificial enclosure is one of the major restoration measures in degraded grassland. In order to find the vegetation niche of enclosed desertification rangeland in semi-arid area, this paper studied the three different treatments (long-term complete enclosure; short-term complete enclosure; short-term incomplete enclosure) in enclosure area which located in Yanchi County of Ningxia. The enclosure area has been divided into the long-term complete enclosure region (E zone), short-term complete enclosure region (E1 zone) and short-term incomplete enclosure region (E2 zone). By analyzing the Levins niche breadth index and Pianka niche overlapping index of 27 kinds of plants in this area, reveal the variation law of plants niche in the arid desert environment, and provide the basis for further analysis of community stability in this region. The results showed that: 1) The niche breadth ofSalsola ruthenica lljin was the biggest in both E zone and E2 zone, which were respectively 0.832 and 0.810. While the dominate species in E1 zone was Lxeris chinensis var.graminifolia, the niche breadth was 0.742. It was their own biological characteristics that decided they can adapt the environment very well in enclosed area, and use the resources of enclosure region very well. The result was that their niche breadth was significantly higher than other species. 2) The analysis of the different plants' niche breadth in three areas revealed that: in terms of community stability, E2 zone was worse than E1 zone, and better than E zone. The long-term fencing enclosure was unfavorable for community stability. While short-term complete enclosure was more beneficial for community stability than incomplete enclosure. 3) By analyzing niche overlapping between different plants species in three areas drawn, the maximum niche overlapping value in E area appeared between Saussurea amara,Sophora alopecuroides L,Agropyron mongolicum Kengand Artemisia hedinii, both were 0.98. The maximum value in E1 area was betweenLespedeza davurica andAstragalus melilotoides (0.82), in E2 area was betweenAstragalus melilotoides andAgropyron cristatum(0.99). Correlation analysis showed that there was no clear linear relationship between niche breadth and niche overlapping. There may have narrow niche overlapping between narrow niche breadths species, the opposite is low, but not exactly so.%人工封育是草场恢复和重建的一种主要措施。为研究半干旱区人工封育草地植物种群生态位，以宁夏盐池县人工封育区3种不同处理方式（长期完全封育、短期完全封育、短期不完全封育）为研究对象，将封育区分为封育核心区（E区）、封育边缘区（E1区）和封育外围区（E2区），通过分析在该地区出现的27种植物种群的Levins生态位宽度指数和Pianka生态位重叠指数，揭示植物种群生态位在干旱荒漠环境下的变化规律，为进一步分析该地区群落稳定性提供依据。研究结果表明：1）核心区和外围区生态位宽度最大的都是刺沙蓬Salsola ruthenicalljin，分别为0.832和0.810，而边缘区生态位宽度最大的是丝叶山苦荬Lxeris chinensisvar. graminifolia，为0.742，这2种植物的生物学特性决定了它们能够很好的适应封育区的环境，并很好的利用封育区的资源，结果是它们的生态位宽度明显高于其他物种。2）对三区内不同植物种群的生态位宽度分析结果显示，三区的群落稳定性表现为E1区>E2区>E区；长期的完全封育并不利于封育区内植物群落的稳定；而短期的完全封育措施比不完全封育措施更有利于植被群落的稳定。3）通过分析三区内不同植物种之间的生态位重叠得出，E区生态位重叠最大值出现在草地风毛菊Saussurea amara、苦豆子Sophora alopecuroidesL、沙芦草Agropyron mongolicumKeng与臭蒿Artemisia hedinii之间，都是0.98。E1区生态位重叠最大值是达乌里胡枝子Lespedeza davurica和草木樨状黄芪Astragalus melilotoides之间（0.82）。E2区生态位重叠最大的一对是草木樨状黄芪和冰草Agropyron cristatum （0.99）。相关分析表明：生态位宽度与生态位重叠之间并没有明确的线性关系。生态位宽度窄的物种之间可能有较高的生态位重叠，反之，则较低，但并不是完全如此。
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