Abstract: This study uses the WAVEWATCH-Ⅲ(WW3)and SWAN to simulate typhoon waves, which have greater influence on the Qinzhou Bay, The simulations are for the period during 1949 2005. Based on the simulation, the authors the Pearson Ⅲ (P-Ⅲ) method to calculate the extreme wave parameters for return periods in deep water outside the Qinzhou Bay. They also simulate the typhoon waves that have greater influence on the Qinzhou Bay under the condition of high tide with return period of 100 years and under the condition of high tide with return period of 100 years plus storm surge with return period of 100 years in the Qinzhou Bay. The P-Ⅲ is again used to calculate the extreme wave parameters for the return periods of the statistical points in the inner Qinzhou Bay in these simulations. The result shows that because of many shallow basins in the Qinzhou Bay, the wave energy is lost significantly due to the bottom friction during the wave propagation, the wave height in the bay mouth is bigger than that in the inner Bay, The physical processes including the wave dissipation and wave transformation are more intense in the inner Qinzhou Bay. The statistical point C1 is near the shore, so its wave parameter is the smallest. The maximum wave height rapidly weakens shoreward and spreads along the eastern shoreline. Under the condition of extreme weather, the ocean wave is breaking and the wave height is damped significantly during the wave propagation process.

Key words: Qinzhou Bay, wave model, P-Ⅲ method, extreme for return period