The research be conducted in January 2017. Observation of mangrove forest density and was done in mangrove forest area in Puteri Sembilan Village, North Rupat Sub-district, Bengkalis Regency, Riau Province. The purpose of this research is to know the structure of mangrove vegetation in Desa Puteri Sembilan. In this study concluded that there are 7 species of mangroves namely: Rhizophora mucronata, Bruguiera gymnorhiza. B. sexangula, Kandelia candel, Aegiceras floridum, Amyena gravis and Avicennia alba. Based on the index of type diversity, station I was categorized as low with value of H '= 1,5131. Station II index of diversity of type including low category with value H' = 1,094 and at station III index of diversity type still belongs to low category with value H '= 1, 2284. Keywords: Mangrove, Community Structure Mangrove Vegetation, Bengkalis