Abstract:The dynamics of species composition, spatial structures and species diversity as well as biomass were analyzed in a four-year successional process of coniferous and broad-leaved mixed forest in Dinghushan Nature Reserve in Guangdong. No obvious changes were observed in species composition in tree, shrub and herb layers in community, but the number of individuals changed greatly. The dominant conifer Pinus massoniana declinedgradually, whereas broad-leaved species, such as Schima superba and Castanopsis chinensis，and mesophytes (Ardisia quinquegona and Psychotria rubra) increased．The whole community was changing into evergreen broadleaved forest．Biomass in tree layer increased and that in shrub layer decreased．The species richness，diversity index，evenness index and ecological dominance in each layer had only a slight change，which indicated that the succession of coniferous and broad-leaved mixed forest in Dinghushan was a slow and relatively stable process． With the succession process， some rare species such as Glochidion eriocarpum and Mallotus apelta disappeared， furthermore，the endangered species Aquilaria sinensis decreased from 25 to 12 individuals within four years，to which attention should be paid.