Research on the ecological species groups and interspecific association of plant species are helpful to discover species coexistence processes and mechanisms, and to more fully understand plant community structure, function, and its taxonomy. However, little is known about the ecological species groups(ESG) and the interspecific association of dominant species in Daiyun Mountain National Nature Reserve of Fujian Province, China. Therefore, the main goal of this paper is to explore the ESG using maximal tree, and to analyze interspecific associations of 32 dominant species selected from 102 sample plots using the chi-square test. The results show that:(1) 32 dominant species have a significant overall positive interspecific association, which indicates that the natural forest in Daiyun Mountain National Nature Reserve is stable,(2) The species pairs with weak associations, non-associations and positiveassociations account for 10.88%, 29.64% and 59.48% of the total 496 species pairs respectively, which suggests that the population distributions of the dominant species investigated are relatively independent,(3) The following species pairs may be useful for practical application, , , , , , , and(4) The results of clustering analysis based on the maximal tree method indicates that the 32 dominant species can be divided into 3 ESGs when λ at 0.60, that is ESGⅠ{Pinus massoniana, Cunning hamia lanceolata}, ESG Ⅱ{P. taiwanensis, R. farrerae, Enkianthus quinqueflorus}, ESG Ⅲ {C. carlesii, A. chinensis, C. eyrei, Castanopsis fabri, C. fargesii, Schima superba, Machilus thunbergii, Rhododendron latoucheae}. The results may be used for the selection of afforestation tree species in South China Forest Areas and guide the natural management of plantations. Research on the ecological species groups and interspecific association of plant species are helpful to discover species coexistence processes and mechanisms, and to more fully understand plant community structure, function, and its taxonomy. However, little is known about the ecological species groups (ESG) and the interspecific association of dominant species in Daiyun Mountain National Nature Reserve of Fujian Province, China. Thus, the main goal of this paper is to explore the ESG using maximal tree, and to analyze interspecific associations of 32 dominant species selected from 102 sample plots using the chi-square test. The results show that: (1) 32 dominant species have a significant overall positive interspecific association, which indicates that the natural forest in Daiyun Mountain National Nature Reserve is stable, (2) The species pairs with askew , non-associations and positiveassociations account for 10.88%, 29.64% and 59.48% of the total 496 species pairs resp ectively, which suggests that the population distributions of the dominant species investigated are relatively independent (3) The following species pairs may be useful for practical application, , , , , , , and (4) The results of clustering analysis based on the maximal tree method indicates that the 32 dominant species can be divided into 3 ESGs when λ at 0.60, that is ESGI {Pinus massoniana, Cunning hamia lanceolata}, ESG II {P. Taiwanensis, R. farrerae, Enkianthus quinqueflorus}, ESG III {C. carlesii, A. Chinensis, C. eyrei, Castanopsis fabri, C. fargesii, Schima superba, Machilus thunbergii, Rhododendron latoucheae}. The results may be used for the selection of afforestation tree species in South China Forest Areas and guide the natural management of plantat ions.