In order to study the characteristics of crustal structure and geodynamics in the Vietnam Sea and adjacent areas, all available data and results of survey and investigation on geology, geotectonics and geophysics for about 50 last years have been accumulated and the complex and systematic methods for analysis and interpretation of data sources have been built to determine the quantitative and detailed characteristics of horizontal and vertical layers of the Earth crust. In the base of the comprehensive analysis of available and updated d~ta, the map of geophysical fields (such as gravity, magnetic field, seismology, heat flow), bathymetry, structure of the main boundaries in the Earth crust, structure and geodynamic of the fault systems have been compiled With use of the deep crustal structure and geodynamics characteristics on the maps the earthquake source zones and their source parameters have been determined and i'n this base some tsunami scenarios that may be caused by these sources have been developed and calculated. The results of the earthquake and Tsunami hazards assessment presented in the maps of scale 1:500,000 and larger scale reflect ihe picture of differenced earthquake and Tsunami hazard with some areas of relatively high and clear hazards in the Vietnam sea and coastal zones.