Combined with Holland gradient wind field and CCMP wind field,based on the third-generation wave numerical model SWAN,we carry out a numerical simulation of wind wave field under the influence of 0515 typhoon “Khanun”,and verify the simulated wind speed and significant wave height by the data of Jason-1 satellite.On this basis，we move the “Khanun” path eastward,establish eight typhoon paths including original path,and study significant wave height of each branch of the Yangtze River estuary under different typhoon paths.The results show that when typhoon paths cover whole Yangtze River estuary,significant wave height of each branch is larger,and from western or eastern side,the impact is relatively smaller.When typhoon paths near estuary entrance,wave height of northern branch and channel is larger.When typhoon paths near southern branch,wave height of southern branch and channel is larger.When the path of typhoon is crossing the Yangtze River estuary,the impact on outside entrance is larger than inside entrance.The maximum value outside the entrance is between 2 m and 3 m,and the maximum value inside is between 1 m and 2 m.