Abstract:Wood structure of six Sonneratia species from Mangrove Nature Reserve at Dongzhai Port, Hainan Province, was observed under LM, SEM and Laser scanning confocal microscope. Ray height and ray width can be used for diagnostic or subsidiary diagnostic features to distinguish S. ovata from other Sonneratia species.Sonneratia forms a monophyletic group which has a closer affinity to Lagerstroemia (Lythraceae) instead of Duabanga (Sonneraceae). The result of clustering based on quantitative data of vessel elements (pores) suggests that the Sonneratia species evolved into two clades，one including S. aseoalris and S．paracaseolaris that has the wider vessel and lower pore density sug esting a high conducting eficiency，the other including S．alba，S. ovata，S．apetala and S．hainanensis that has the narrower vessel and higher pore density resulting in high conducting safety．