| Water resources in China is excessive in South and few in North, which is not compatible with the productivity distribution in our country. The contradiction between water supply and water demand is most striking in Beijing, Tianjin and north china area. With the increasing of population and the development of economics, the contradiction between water supply and water demand is increasingly outstanding, what's worse, many ecological environmental problems are caused , which not only restricts the normal development. Of development of local economics, but also even influences the sustainable development of social economy. In order to solve these problems, China implements the South-to-North water transfer project.The South-to-North Water Transfer project is an important project in our country, having the important strategic signification. From the angle of ecological environment, the middle route project is not only an inter-basin water transfer project, but also a magnificent ecological environment project. Since the bad influence of water transfer on ecological environment is mainly in the water transfer area. Therefore, protecting the ecological environment of water source areas is an important objective in implementing the South-to-North water transfer project. The water source areas of the middle-line project of Transferring Water from South to North are mainly in the Mountain Areas, including a large area of slope farmland. To protect the ecological environment of water source areas and avoid soil and water loss, our country implements the strategies of conversion of cropland to forest/grass and ecological restoration engineering. Then a large area of abandoned lands are made and those abandoned lands are a turning point of the development of ecosystem from retrogressive succession to progressive succession. Vegetation restoration and reconstruction in the abandoned lands have been a meaningful study subject.This paper sets Zhaigou area in Ningshan county in the water source areas of the middle-line project of Transferring Water from South to North as its study object. It explores community types, structures, niche, distribution patterns, species diversity of plants of abandoned lands of this process of succession and the relations among major species, advices on restoration of the ecosystems of this area . The major results are as follows: This paper analyses the constitution of flora and categories of plant community in the research area according to the survey on the plant species of sample plot after natural recovery in the range of one to twenty years abandoned lands. It is shown that species in the research area mainly consists of Compositae.,Gramineae and Rosacea. Because the plant community haven't reached the climax stage of succession of herbaceous plants and many plants are still in the early state of secondary bare area plants covering, consequently, plants of single family single genus,single family single species and single genus and single family take up a comparatively higher proportion. The flora mainly consists of northern temperate element and Cosmopolitan distribution type. According to the principle of phytocoenology-ecology, plant community in the research area can be divided into one vegetation type, two formation groups and six associations.By studying the soil, bulk density, moisture content, organic matter, the content of organic matter, various underground biomass and above ground biomass in different sample plot, the property of the soil and a close relationship between the biomass of various plants and the abandoned time of different plant communities will be found. In the range of 0-30cm soil layer, soil bulkdensity is reducing with the increase of the time of abandoned land. After four-year returning farmland, soil water content attains a comparatively steady level, the average soil water content is 18.54-22.10%.Plant community's succession stage of abandoned lands from one to twenty years long can be divided into four succession stages by studying PCA ordination and cluster analysis of plant community in seven sample plots.Choosing species diversity index such as Odum,Margalef,Hurlbert,Gleason,Whittaker,Audair, Goff,Simpson, etc. to measure species diversity of community in different succession stages. The result shows that species diversity index of community has a close relationship with the years after returning farmland, the longer the time after returning farmland, the longer the time for succession of plant community in sample plot, then the more of the species.quantities, the more complicated community structure, the higher of the species diversity index. Otherwise, the species diversity index of plant community will be low.By using Levins and Shaanon-Wiener's index to measure the nicheof species in the plant community in different succession stages and Petraitis's general overlapping index and separation index of niche to calculate the niche overlap of the population in plant community in different succession stages, the results we've achieved are that the bigger the niche breadth of plant community, the more capable to adapt to the new environment and to use the resources. The bigger range of the niche overlap is, the bigger the niche similarities between plant communities and the higher level of the similarities to use resources.Through investigation and research on plant community in research area, This paper thinks that Conyza Canadensis,Artemisia argyi,Erigeron annuus,Duchesnea indica,Carex lanceolata,Houttuynia cordata and Imperata cylindrical can be used as alternative plants of local plants in the herbaceous succession stage of abandoned framlands plant restoration in this area.
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