This article researches the sensitive factors，which influence the wave dynamics impacting on the channel development during the flood and dry season,and the influence mechanism in the mouth bars of the Yangtze River estuary.Some perceptions are as follows:1)the wave period and direction are two sensitive factors and their changes play a significant part in the sediment movement;2)for the short-period waves,the impact on the riverbed is mainly in the shallow water,while for the long-period waves,the influence occurs both in the shallow water and the deep water;3)usually,the total wave energy dissipation in the mouth bars caused by on-shore wind and off-shore wind differs in an order of magnitude at least;4)during the dry season,the off-shore wind is primary,and the wave characteristics are short-period,steep,scattered and low-energy;while during the flood season,the on-shore wind is prior,and the waves show long-period,rounded,regular and high-energy.