Characteristics of dynamic geomorphology of coastal-river mouth zones of Ma river of Thanh Hoa province Reasearch on dynamic geomorphological characteristics of coastal-river mouth zones song Ma of Thanh Hoa areas has an important significance which is useful in using and exploiting rationally the territory and developing sustainably social-economics.Main factors affecting recent dynamic processes in the coastal-river mouth zones song Ma of Thanh Hoa are included: river flows, nearshore currents and active tectonic movements of the earth crust; they control the formation and development of modern topography at the coastal-river mouth zones.Sedimentary accumulating controls formation of banks, bars, mounds, dunes and Holocene-Recent plains at the region of Len and Hoi river mouth. In particular, at Len mouth, high accumulation rate controls forming plains, banks, bars, mounds with seaward aggradational rate of 40-50 m/yr; at Hoi mouth, because the source material of low flow, so deposition weak and mostly along the coast in the north and south of the Hoi mouth. The deposition speed reaches 10m/year.Strong erosional processes are developed at nearshore regions of less dense sediment, small river mouths or no river mouth, or occurence of active faults, such as Lach Truong mouth and in river bank of Hoi mouth.Maximum erosion in Cửa Lach Truong with speed 5-6 m/year; Cua Hoi weaker, erosion rate was only 3-5 m/year.