Abstract: Interspecific association of the dominant species in three communities with the endangered plant Euonymus chloranthoides,at Beiwenquan site,Jigongshan site and Dongwenquan site,respectively,was analyzed using variance ratio,X²-test and noncentred indices.Results showed that overall interspecific association had a non-significant negative relationship for the three communities.Of fifteen species-pairs for six species at Beiwenquan site,seven species-pairs showed positive association and eight species-pairs showed negative association.Of twenty-eight species-pairs for eight species at Jigongshan site,eleven species-pairs showed positive association,sixteen showed negative association,and one held relatively independent.Of six species-pairs for four species at Dongwenquan site,two species-pairs showed positive association and four showed negative association.Interspecific association indicated that these communities were not steady,which was closely related to habitat fragmentation.High positive association between E.chloranthoides and Sinoalamus affinis indicated that it was necessary to provide suitable habitat for E.chloranthoides by pre-construction of S.affinis population.