Research conclusions: In the past one hundred years，the sea level of the South China Sea raised by an annual average of 20mm，with the tendency of raising more and more year by year． As the prediction of the raise amplitude raise of the sea level is rather complicated，on consideration of the factors of the sea level raise in theory，the abnormal fluctuations of the sea level，the raise of the flood and tidewater and the topography change，it is predicted that the sea level along the Pearl River Delta region will raise to 22 ～33 cm by 2 030 and it will produce the raise of underground water in this area．