Abstract: We simulate the effect of strong waves on the sediment transport at the Xiaoqing River estuary areas using the 3D model ECOM SED(Estuarine Coasta lO cean Model with sedmient transport) with the wave parameters from the wave model SWAN(Simulating Waves Nearshore).The water depth,tidal current,suspended sedmient and historicalm eteorological data are used to estmiate the changes of the suspended sediment concen trations(SSC) and the bed scour and siltation(BSS) caused by strong wind and waves.We compare the smiulation with the in situ data and findthat the results are reliable.Results show that the sedmient transport change greatly under the influence of strong wind and waves in the near shore areas.The value of SSC is 10 times larger than that under the normal wind and wave condition.The change of BSS could be even as much as one hundred times.The result also show that the change of BSS resulting from strong wind and waves would have a great impact on the evolution of river estuary sandbars.