The coverage of ground station obtained via the traditional method based on the visual domain analysis can not accurately describe the practical performance of the system coverage. An irregular topography ADS-B ground station signal coverage analysis method is proposed in this paper. First, according to the characteristics of the irregular topography channel, specific simulation algorithm of Longley-Rice model is derived, and the model is used to simulate the ground-to-air communications channel. Second, the antenna that meets the requirements of ADS-B standard is simulated, and the radiation range of signal in free space is calculated out. Then, analysis is made to the sightline range cut-off caused by terrain shading. Finally, taking a certain area as an example, comparison is made with other algorithms by verifying the forecast range with the actual data. Experimental results show that: 1)The irregular topography is the key factor influencing the ground station signal coverage; and 2)Longley-Rice model can accurately simulate signal attenuation. The method in this paper provides a theoretical support for the location selecting of ground station.