Abstract: To solve the deployment problem of ground decoy under mountain condition, a simulation model of decoy effectiveness is established based on the working principles of decoy and anti-radiation weapon. According to the position relationship between anti-radiation weapon and decoy, the signal pitch angle is compared with the slope of the mountain in the same direction, and whether the anti-radiation weapon and decoy meet the intervisibility condition is then determined. At the same time, considering several simulation conditions such as strong signal exposure and sequential change of decoy, the simulation of anti-radiation attack under mountain condition is achieved. The damage probability of the main source and decoy, as well as the distribution map of anti-radiation weapon landing points, are used to evaluate the decoy effectiveness. Taking a mountain slope of 45 ° as an example, simulation analysis is conducted on the damage probability of each radiation source when anti-radiation weapons attack from different directions. The results show that the decoy needs to be deployed in advance when the mountain slope is large. The simulation analysis method can effectively evaluate the effects of the decoy array method, decoy array distance, and mountain slope on decoy effectiveness, which has important guiding significance for the rational deployment of decoy in different application scenarios.