Abstract: An analysis method of electromagnetic propagation mode is proposed in this paper. By estimating the parameters of Paulus-Jeske (PJ) model, a complete model of evaporation duct is realized. The parabolic equation model is used to analyze the two-dimensional electromagnetic path loss distribution in meteorological environment, the maximum pooling is applied to reduce the data, and the adaptive cluster analysis is used to analyze the electromagnetic propagation pattern. The mapping between the sea clutter attenuation and electromagnetic propagation pattern is established, and the conditional probability is calculated. The results show that there is a correlation between the sea clutter attenuation and electromagnetic propagation pattern in evaporation duct environment. The analysis results show the electromagnetic propagation pattern in evaporation duct and provide a priori conditional probability analysis for refractivity from clutter method.