A new method was presented using satellite remote sensing data in the calculation of topography and flooding at littoral zone. Flooding lines were drawn from high resolution satellite remote sensing images at different tidal level, and the topography of littoral zone was calculated with these lines. Then, the littoral zone topography was applied in the calcuation of flooding, which was checked with the satellite remote sensing images. Based on this method, the littoral zone flooding lines in Zhanjiang Harbor of China were analyzed by Landsat satellite remote sensing images, and the littoral topography and flooding were calculated.