Employing the succession series of Kandelia candel-Aegiceras corniculatum community in non-indigenous species Sonneratia apetala extension area as resource axes, and with three axes, commonly used calculation formulae, this paper determined the niche breadth and overlap of mangrove populations. The results showed that the niche breadth decreased in order of Aegiceras corniculatum (3.8357) > Kandelia candel (3.3421) > Bruguiera gymnorrhiza (3.3180) > Avicennia marina (3.0975) > Sonneratia apetala (2.9137) > Sonneratia caseolaris (2.5724) > Ceriops tagal (1.8523) > Rhizophora stylosa (1.6897) > Bruguiera sexangula (1.0000), which could indicate the ecological adaptability and distribution range of the species. The niche overlap among K. candel, A. corniculatum, B. gymnorrhiza and A. marina was the largest, suggesting the intense competition among them, followed by the niche overlap of S. apetala with S. caseolaris, A. corniculatum, K. candel and A. marina, S. apetala with R. stylosa and B. sexangula, S. apetala with C. tagal, and S. apetala with B. sexangula.