The relationship between nutritional status - sediment bacteria and mangrove plant growth was examined to lay a foundation of the coastal green belt recovery and expansion at Ganh Hao, Bac Lieu. The elevation of topography above the mud flat probably prevented the inner area from saltwashing by tidal water, resulted in the extremely high salinity of the sediment. The plant growth in the dry section, therefore, was low. Sediment humidity and salinity strongly affected the nutritional status through their effects on the distribution and activity of Vibrios and Enterobacters, which can take parts in the nitrogen and phosphorus cycling. The strong growth of Avicennia lanata at the mudflat probably resultedfrom the abundance of sediment bacteria.