Abstract:In order to understand the stability of mixed forest community of Casuarina equisetifolia and Dendrocalamus minor var. amoenus in the coastal windbreak of Dongshan Island, China, the inter-specific association and niche of the community was analyzed by using quadrat method. The results showed that there was no significant positive correlation among inter-specific associations as a whole (VR=1.72, W=20.625), indicating that the community was in an unstable dynamic succession state. Two species pairs; D. minor var. amoenus and Lantana camara, U. procumbens and C. equisetifolia had high association and co-occurrence (PC ≥ 0.7, OI ≥ 0.8, DI ≥ 0.8). The niche width of invasive plant L. camara was high, and the niche overlap with D. minor var. amoenus was high, showing high positive correlation, making the population in an unstable state. The habitats of the coastal windbreak was simple, and the habits of dominant species were similar, so there was a strong positive interspecific association between D. minor var. amoenus and other most species. Restricted by environmental resources, the strong positive association was related to the large niche width of species. The strong positive interspecific association of species pairs and the potential competitive advantage of alien species might be an important factor affecting the stability of the community.