The tide and the storm surge are two major contributions to the coastal seawater level of Vietnam and its combination is a crucial parameter for the base high of the coastal structures. In order to specify the basic chracteristics of sea water level heights to assistant the coastal engineering and design, in this paper the obtained results on the annual exceedance probabality (as well as return period) of seawater level height (tides plus storm surges) are presented. On the basis of the historical typhoons occurred in East Sea, more than 5,000 artificial storms (equivalent to 1,000 years) are genarated by using Monte Carlo method as well as statistical distributions of typhoon parameters. The numerical model is applied to calculate the harmonic constants of 10 tidal constituents as well as surges caused by more than 5,000 storms at each of 240 points along the shore. The calculated results of typhoon surges and the water level of the 19 year tide are explored to build up the annual exceedance probability (as well return period) curves at 240 points along the shore of Vietnam. These are the crucial basic parameter for the coastal design and construction.