In order to analyze the structure and variation of plant communities in Yanchi county, Ningxia, a population of plants emerging after cultivation was surveyed and the studied area was divided into three areas:core area (E), edge area (E1) and peripheral area (E2). Samples of the plant population were recorded according to species, abundance, coverage, height, and biomass. They were analyzed in respect to diversity indices (species diversity index, community dominant concentration index, community evenness index and species richness index), principal component analysis and polar ordination. The results showed that the dominant species after cultivation and recovery in Yanchi County, Ningxia are from the genera compositae and leguminosae. Four random samples each of 1m2 were examined. Sample area E contained 9 families and 21 species in 2011, 7 families and 20 species in 2012, and 9 families and 22 species in 2013. The genera compositae and leguminosae accounted for 52.4%of the total population in 2011, and for 50.0%in 2012 and in 2013. Sample area E1 had 8 families and 18 species in 2011, 7 families and 16 species in 2012, and 9 families and 16 species in 2013. Compositae and leguminosae accounted for 55.6% in 2011, and for 50.0% in 2012 and in 2013. Sample area E2 had 6 families and 15 species in 2011, 8 families and 19 species in 2012, and 9 families and 17 species in 2013. Compositae and leguminosae accounted for 60.0% in 2011, for 47.4% in 2012 and for 35.3% in 2013. The number of species of sample area E2 was the lowest, and the dominant position of species in the genera (leguminosae and compositae) in all kinds of sample areas were gradually weakened, and the grassland vegetation community tended to be stable. The diversity index, and evenness index of E2 was the lowest, and the advantage of concentration index was the highest. In all sample areas, the diversity index was significantly correlated with the evenness index and the richness index. The results of principal component analysis showed that the main environmental factors affecting the sample E were content of rapidly available P in soil surface, and soil moisture content at the depths of 0~10 cm and 20~30 cm. For the sample E1 the factors were content of rapidly available P and organic matter in the soil surface, and soil moisture content at depths of 0~10 cm and 20~30 cm. For the sample E2 the main environmental factors affecting the population were content of rapidly available K in the soil surface, and soil moisture content from 20~30 cm. The figures of polar ordination showed that the quadrats forming sample E were the most similar and the population of plants was relatively single. Therefore, it was concluded that the best time to cultivate in Yanchi is 2~3 years. And with 2~3 years as a cycle of rotational grazing can better promote the grassland restoration so that it can be kept the balance of the grassland ecosystem.%为探究宁夏盐池人工封育区植物群落的结构和变化规律，将研究区划分为核心区（E）、边缘区（E1）、外围区（E2）3个区域，采用小样方法对各区域内的植物种名、株数、盖度、高度、生物量等进行调查，并结合多样性指数（物种多样性指数、群落优势集中性指数、群落均匀度指数和物种丰富度指数）、主分量分析和极点排序的方法对其进行分析。结果表明：宁夏盐池人工封育区以菊科和豆科为优势种，区域E 2011年共有植物9科21种，菊科和豆科占52.4%；2012年共有植物7科20种，菊科和豆科占50.0%；2013年共有植物9科22种，菊科和豆科占50.0%。区域E12011年共有植物8科18种，菊科和豆科占55.6%；2012年共有植物7科16种，菊科和豆科占50.0%；2013年共有植物9科16种，菊科和豆科占50.0%。区域E22011年共有植物6科15种，菊科和豆科占60.0%；2012年共有植物8科19种，菊科和豆科占47.4%；2013年共有植物9科17种，菊科和豆科占35.3%。区域E2物种数量较少，各区域优势种（豆科和菊科）的优势地位随着封育年限的增加逐渐减弱，草原植被群落趋于稳定。区域E2植物群落多样性指数、均匀度指数均为3个区域中最低，而优势集中性指数以 E2最高。各区域植物群落的多样性指数、均匀度指数和丰富度指数表现一致。主分量分析的结果显示影响核心区植物群落的主要环境因子为表层土壤速效P含量、0~10 cm和20~30 cm土壤含水量，影响边缘区植物群落的主要环境因子为表层土壤速效P、有机质含量以及0~10 cm和20~30 cm土壤含水量，而影响外围区植物群落的主要环境因子为表层土壤速效K含量、20~30 cm土壤含水量。极点排序图表明区域E各样方间相似性较高，植被群落单一。建议盐池县的封育年限以2~3 a为周期进行轮牧，以保持草地生态系统的平衡。
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