Abstract: In order to analyze the main factors that affect the radio wave propagation in the tropospheric environment,the propagation characteristics of radio waves in complex land-ocean environment using the parabolic equation model is studied in this paper. The Miller-Brown approximation for rough sea surface, terrain masking approach and the piecewise linear shift map method are taken into account, and the effects of island, coastal city, evaporation waveguide, transmission antenna parameters and wind speed on the propagation of radio waves are analyzed. The results show that the propagation loss is greatly affected by evaporation duct, island′s height, and frequency, while it is less affected by the wind speed over the sea in long-distance propagation. Besides, the existence of islands will cause multipath effect, and its shadowing effect will also increase the propagation loss. In addition, the coastal geographical environment also has a greater impact on the propagation loss, and with the increase of height, the effect gradually decreases. Therefore, increasing the height of the transmitting antenna can effectively extend the detection range. These results have important guiding significance for the design and performance evaluation of radar systems.