Utilizing spherical nonlinear shallow water equation this paper studies the impact of the 11 March 2011 Japan M9.0 earthquake tsunami on southeastern seaboard region of China, and calculates potential tsunamis induced by strong earthquakes in three different sections of Okinawa trough. Then, the relation between wave heights and arrival times of the Japan tsunami and the simulated tsunamis is analyzed. The result indicates that the simulated Japan tsunami is consistent with local reports of Japan and the repots from 7 tide gauge stations on coastal line of southeastern China.