Abstract: By conducting the normal computation for the tidal current and wave mathematical modelling and sediment transportation, the dynamic causes and quantification results of the evolution of erosion and sedimentation on coastal shore area can be obtained, but it is difficult to get the total amount and the distribution character of the scour and silt. By using the technique of satellite RS(remote sensing) combined with GIS (geographic information system), the measured underwater topographic map and synchronous RS data can be provided, and a satisfying correlation model of RS fathoming can be set up. At the same time, the total amount,area and distribution of the scour and silting of all levels in various time intervals before and after the construction can also be obtained. So the combination of mathematical model and RS technique is an effective way to further perfect the computation of erosion and sedimentation . In this paper, a practical example is introduced to estimate the evolution of erosion and sedimentation caused by coastal engineering using the method mentioned above.