The development of coastal mangrove forests under the influence of hydrodynamics is studied and analyzed. The results from field observations, calculations as well as simulation were done and applied in Nang Hai mangrove site and the mangrove site influenced by Durian storm-2006 in Can Gio, Ho Chi Minh city. Results prove that the young mangrove could grow up due to seasons and destroyed by wave impact. Moreover, the initial studied results also show that the contribution of tidal water level in the rehabilitation and dispersion of the mangrove seeds.