Abstract:Shannon-wiener index, Levins index and comparability proportion formula were used to study niche breadth and niche overlap of dominant species in Tsuga longibracteata forest gaps at different stages. Tsuga longibrocteata, an endemic to China species of Pinaceae, is distributed at the uppermost layer of forest, which makes it difficult to regenerate naturally. The study of ecological niche in gaps of T. longibracteata forest is to understand the change in population number of some species, the regeneration of which depends on gaps, and to protect the forest resource more effectively. The sites studied were located in Tianbaoyan National Nature Reserve in Fujian Province. Twenty one gaps, with quadrats of 80 m2 each were investigated, The results revealed that niche breadth of main trees in gaps varied at different stages of gap development. At early stage, niche breadth of tree species declined in the following order： Tsuga longibracteata, Castanopsis carlesii, Schima superba, Castanopsis eyrei, Michelia maudiae, Cinnamomum subavenium, Cyclobalanopsis glauca, Rhododendron iniarum, Symplocos sumuntia, Cyclobalanopsis myrsinaefolia； at the middle stage, in the descending order of： Castanopsis carlesii, Schima superba, Tsuga longibrctcteata, Cinnamomum subavenium, Michelia maudioe, Symplocos sumuntia, Castanopsis eyrei, Rhododendron iniarum, Cyclobalanopsis glauca, Cyclobalanopsis myrsinaefolia； while at the late stage, Castanopsis carlesii, Schima superba, Tsuga longibracteata, Cyclobalanopsis glauca, Cyclobalanopsis myrsinae, Cinnamomum subavenium, Michelia maudiae, Cyclobalanopsis myrsinaefolia, Castanopsis eyrei,Rhododendron iniarum. High values of niche overlap were shown in all trees in gaps with different stages, but then the values declined with the gap development. Less niche overlap values were shown in T. longibraeteata compared to those species with higher niche breadth, but more to those with lower niche breadth.