| When waves propagate into nearshore shallow water from deep water, wave refraction, diffraction, reflection and breaking etc., may be caused by the island, bathymetry change, coastal structures and so on. It is very important to accurately predict the wave field nearshore or in the harbor for the port and coastal engineering. Many numerical models of near-shore wave transformation have been developed, however, the comparison of applicability of different models are few at present. In this thesis, based on summing up the development of wave models, SWAN model, CGWAVE model and MIKE21-BW model, that are respectively based on the action spectra balance equation, the elliptic mild-slope equation and Boussinesq equation, were compared. The main contents and conclusions of this work are as follows:(1) By comparing the results of the three models, it is found that the diffraction result of the CGWAVE model coincides with analytical result best when the regular waves and irregular waves propagate into the semi-infinite breakwater with = 0.3. The CGWAVE model was recommended for the similar condition while the SWAN model can be used for multi-directional waves. d /L(2) By comparing the simulated results of the three models, it is found that the simulated diffraction of BW model agrees with the experiment best when the regular waves and irregular waves propagate over the elliptical shoal with d /L<0.2.(3) For wave breaking simulation, it is found that the BW model is the best one that coincides with the experiment when the regular wave propagates on a plane and bar beach.(4) For wave breaking simulation at the condition that irregular waves propagate on a beach at an angle, it is found that the BW model and the SWAN model can agree with the experimental results similarly(5) By comparing the results of the three models, it is found that that the SWAN model is more suitable to the wave simulation in the large area and the other two models are more suitable to the wave simulation in the small area.
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