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This paper provides some meteo-hydro-dynamical features in Mekong River Mouth area which were based on statistical results from longtime measurement data such as wind, wave, sea water level, and river discharge. Study results show that distribution features of wind and wave characteristics are corresponding to seasonal variation. Predominant wind and wave directions during NE Monsoon period is NE, and in W, SW directions during SW Monsoon period. NE Monsoon period is from November to April (strongest in December and January), SW Monsoon period is from June to September (strongest in August). During NE Monsoon period the wind velocity and wave height were higher than that of SW Monsoon period. Variation of SWL at Vungtau Station shows that the tide is semi-diurnal with maximum value occurred during NE monsoon period (highest in November), and minimum value occurred during SW Monsoon period (lowest in June). Variation of river discharge is similarly at two stations (Mythuan and Cantho). During flood season (from July to December) average monthly discharge was ranged from 4,000 to 15,800 m 3 /s. During dry season (from January to May) average monthly discharge at both stations was less than 4,000 m 3 /s. Statistical data show that Mekong River Mouth area is a region of strong and complicated hydro-dynamical interaction processes between river and sea.

In this paper some indirect calculations of the amplitude and power spectrum of internal wave are presented  on basis of using the continuous temperature data measured at 2 moorings stations in the South-East sea  region of Vietnam. The calculated results show that: In the shallow continental shelf region during the  South-West monsoon, at the depths of 12 - 38 m, the average amplitude of internal wave has the values of 5 -  10 m; Whereas in the more deeper region during North-East monsoon, at the depths of 10 - 60 m, 70 - 220 m and 230 - 600 m, the average amplitude of internal wave has the values of 20 - 80 m,  1 - 5 m and  8 - 15 m  respectively; By using the power spectrum analysis of internal wave show that: The power spectrum of internal wave in the shallow continental region is less than of about 20 times in comparison with the deeper  region; The power spectrum of internal wave in the South-East sea region of Vietnam is complicated and  formed mainly by waves having periods of 3 - 24 hours, among them, the wave components with periods of  12 and 24 hours are dominance. The waves with period smaller than 3 hours are very small power.