The permanent monitoring sample plots were established in the typical area of evergreen and deciduous broad-leaved mixed forest in Qizimeishan National Nature Reserve.The structure and ecological diversities of this ecosystem were investigated using the conventional methods of community types.The finding results showed that:1)According to the analysis of plant population size and importance values of the community,Cyclobalanopsis multinervis,Eurya alata and Carpinus fargesiana sequenced as the top three of abundance and important values in this community,so these three species were the dominant and symbolic species for this community.The typical type of evergreen and deciduous broad-leaved mixed forest in Qizimeishan National Nature Reserve is the Cyclobalanopsis multinervis +Carpinus fargesiana-Eurya alata community.(2)Age structure analysis results presented that the most of the Cyclobalanopsis multinervis,Eurya alata and Carpinus fargesiana were young trees and the most individuals were concentrated in the Ⅰ and Ⅱ diameter classes,and this results suggested the good generation growth,so this population was a typical growing population.(3)The diversity index of Shannon-wiener index,Pielou evenness index and Simpson's diversity Index indicated that the richness and evenness degree of trees’ layer were higher than that in the shrub and grass layers.(4)The most individuals of Cyclobalanopsis multinervis and Eurya alata populations occupied the ecological space below 10 meters,and Carpinus fargesiana and Liquidambar acalycina took up the middle and upper layer space.The plant species occupied different space levels,and the mature individuals would dominate the upper layer space step by step.