Abstract: Under the extreme weather condition, the sediment-water mixture with high concentration that is caused by the wave would give rise to the sudden silting of the channel, and then increases the channel silting volume. Based on the field hydrological data during typhoon Malka, it establishes the three-dimensional tidal current and sediment mathematical model of the Yangtze River Estuary under the wave-current interaction, which is used to study the problem of sudden silting in North Channel. The mathematical model verifies the process of North Channel's water sediment during typhoon Malka, and the result shows that its similarity is better. By separating the wave, the writer discusses the different of sediment concentration and channel siltation under the combined action of both tide and wave flow and studies the influence of the typhoon wave on the silt of channel. The studied results show that the wave of typhoon has a great influence on the sediment concentration with the depth of -15 m in shallow water area. Meanwhile, the sediment concentration of North Channel increases gradually from the upstream to the outside and as a result it changes the distribution trend of sediment concentration as High in the middle and low in both ends of North Channel under the normal weather. The wave of typhoon has less influence to the back silting distribution of inner waterway of North Channel entrance, and the sediment deposition increases dramatically at the outer waterway of North Channel entrance. That is to say that the sudden silting of channel mainly takes place outside the North Channel.