A field plot sampling method was employed to investigate community niche of Castanopsis eyrei forest in Gutian Mountain National Nature Reserve. Parameters of niche breadth, niche similarity and niche overlap were calculated to show community characteristics of 14 dominant species, including Castanopsis eyrei, Schima superba, Cyclobalanopsis glauca, Loropetalum chinensis, Daphniphyllum macropodum, Rhododendron ovatum, Lithocarpus glaber, Rhododendron latoucheae, Castanopsis fargesii, Photinia serrulata, Castanopsis tibetana, Pinus massoniana, Syzygium buxifolium and Vaccinium bracteatum. The results showed that niche breadths of Castanopsis eyrei and Schima superba were larger than other species, with Levins (Bi) and Hurlbert's (Ba) values being 0.8703 and 0.8528, and 0.8446 and 0.7824, respectively. Smaller niche breadths were found for Photinia serrulata, Castanopsis fargesii and Castanopsis tibetana species, with Bi and Ba values being 0.2956 and 0.1359, 0.2953 and 0.1356, and 0.2684 and 0.1064, respectively. The niche similarity between populations increased with niche breadth, as shown between Castanopsis eyrei and Schima superba, between Castanopsis eyrei and Rhododendron ovatum, or between Schima superba and Rhododendron ovatum, similarity values being 0.7630, 0.7252 and 0.6452, respectively. Despite of difference in niche breadth, in addition, large niche similarity existed between Schima superba and Lithocarpus glaber (0.6866) due to their similar habitat requirements. Niche overlap degree between populations increased with niche breadth, which was shown in Castanopsis eyrei, Schima superba and Rhododendron ovatum, etc. Only 39 sets of Castanopsis eyrei forest had niche overlap values greater than 0.1, accounting for 21.4% of the total. Therefore, small niche overlap degree found in this study suggests less fierce interspecies competition in the forest, representing a stable community of the Castanopsis eyrei forest of Gutian Mountain.