Open-pit coal mine could destroy the original natural ecosystem, forming a considerable number of abandoned mining lands, causing a series of ecological problems as well. Revegetation is the core of ecological reconstruction, which has impacts on community characteristics and biological diversity of the vegetation, and does well to the soil physical and chemical properties at the same time. At present, studies on revegetation in mining areas, mainly focusing on the improvement of revegetation technology, the effect of vegetation and soil restoration, and vegetation allocation model, etc. There are less researches on the changes of plant community structure and stability in time series. As an important characteristic of ecosystem structure and function, community stability has an impact on the laws and characteristics of the stability of vegetation. M.Godron index is a classical method for community stability evaluation, but it can only reflect the stability of the plant community without considering the changes of community structure. Therefore, the comprehensive analysis of the stability and composition characteristics of the plant community can further understand the ecological characteristics and restoration process of the plant community in the mining area, which is significant to the ecological restoration of the mining area. In this study, the communities of artificial revegetation of 4 waste dump slopes in Beidian Shengli open-pit coal mine in Xilinguole League of the Inner Mongolia, were phytocoenologically investigated using the method of space-substitute-time. The community characteristics and stability in the process of revegetation of waste dump slope with different restoration years were explored. The species composition, species diversity, and community stability of vegetation were analyzed using diversity index and the optimized M.Godron index. The results showed that:(1) a total of 56 naturally occurring plant species, belonging to 44 genera and 16 families, were observed in the slope of waste dump which mainly composed by Gramineae plants and the major growth type was herbaceous plants. (2) With the increase of restoration years, the life form of plants changed from biennial plants to perennial plants, and the dominant species on slope changed from artificial plants to native plants. (3) On the whole, the species diversity decreased and the community stability increased with the increase of restoration years. (4) Due to the difference of soil micro-environment in different slope directions, the restoration effect and stability of north slope was better than the south. To some extent, these findings can provide a scientific basis for the selection of plant species and rational allocation mode in the process of artificial remediation of open-pit coal mine dump.