Taking the Baidajie embankment in the mainstream of Nenjiang River as the typical area, the locally encrypted and unstructured triangular calculating grid was generated by the surface water modeling system(SMS)based on the complex river topography and coastline conditions. Then, the third generation of shallow water wave model(simulating wave nearshore, SWAN)was adopted to simulate the effect of wave attenuation forest on the wind-generated waves in river. The results show that the correlation coefficient between the simulated wave height and the measured wave height is 0. 95. The coefficient of wave dissipation is 30. 51% under the condition of a flood once in fifty years. It means that the simulating results are reasonable and the anti-wave effect is significant. Meanwhile, the SWAN model based on the unstructured triangular mesh can effectively simulate the wind-generated wave field in the river of complex topography.