Abstract: The community characteristics and quality of Castanopsis eyeri distributed at the Tiantai Mountain of Zhejiang Province are analysed.The Castanopsis eyeri has a striking dominant which shows the monodominant community in the Castanopsis eyeri community.There is complicated vertical structure which can be divided into tree stratum,shrub stratum and herb layer as well as a definite number of interstratum plants.The species diversity index of the tree stratum is a bit low,which has something to do with the monodominant community formed under particular living conditions.There is the very striking similarity of plant species among different plots,and there is a relatively uniform composition of species in the community.The age structures of the dominantpopulation-Castanopsis eyeri and Schima superba belong to stable or increasing type.And the distribution patterns among 10 plots are of clump distribution.