Abstract: In order to predict the influence of signal coverage when the civil aviation navigation equipment failed to meet the operation requirements at a specific location or time, a system of station query and signal coverage evaluation was designed and implemented by taking route and sector coverage as an example. Firstly, the signal coverage was obtained by considering the factors of the distance of sight propagation, the radiation distance of the base station antenna and the line of sight cut-off distance. Then, based on ray method and dichotomy method, the quantitative evaluation algorithm of equipment signal coverage change was established, including distance measurement and area measurement. Finally, the signal coverage changes of the route and sector before and after the equipment failure, including coverage distance or area change, were evaluated quantitatively. Meanwhile, the scene simulation was realized based on the 3D geographic information system, and the coverage changes were visualized in three dimensions, then the evaluation report was generated, which provides necessary data support for emergency disposal and operation safety of equipment failure.