Abstract: Based on the data of 60 plots obtained from investigation, the interspecific relationships among 16 dominant herbage species in Eucalyptus grandis plantation were studied by using χ²-test, Jaccard’s association index test and Spearman’s rank correlation coefficient test, respectively. The results indicated that most species were independently distributed and not closely related with each other. The major of species pairs correlated negatively, which showed the communities were in the phase of succession and the species composition would change. Indicators of interspecific association adding to correlation coefficient was an effective method to study the relationship between species. The 16 dominant species were classified into three ecological species groups. The Species in same ecological species groups had similar resource utilizing ways and ecological requirements, but those in different groups showed apparent differences. The classification of ecological species groups would provide a theoretical basis on managing herb layer in Eucalyptus grandis plantation.