At present,the numerical model can hardly simulate the characteristics of the multi-directional and irregular nature of the natural wave.Based on the overall physical model test of the port wave,we study the distribution law of the wave height disturbance coefficient of the measured point in the harbor under the action of the irregular wave.The results show that in the shielding area dominated by the diffraction effect,the diffraction performance of the multi-directional wave is greater than that of the unidirectional wave,and the wave disturbance coefficient is larger.Wave diffraction and reflection are very strong coverage area,multi-directional irregular wave and unidirectional irregular wave disturbance coefficient cannot see the obvious size relationship.In the well-covered area dominated by the diffraction,the disturbance coefficient of unidirectional irregular wave is larger than that of multi-directional irregular wave,and the larger the reflection coefficient is,the larger the disturbance coefficient of unidirectional irregular wave is.In the shield area dominated by the diffraction,the wave distribution is less sensitive to the period.The wave height distribution is more sensitive to the period in the well-covered area which is dominated by the reflection.In the case of diffraction and reflection,it is possible that the wave height in the port under unidirectional wave is larger than that of unidirectional wave,and it is safe to use unidirectional irregular wave to simulate it.In the case of the overall model test,it is necessary to make a comprehensive consideration based on the actual engineering conditions to determine the wave type.If necessary,two kinds of unidirectional and multi-directional irregular waves should be tested to determine the best scheme.