Abstract: The propagation loss calculation accuracy is low in the long distance, irregular and complex terrain, according to the actual terrain, this paper proposes an algorithm model based on geographic information system to improve the accuracy of wave propagation loss , and constructs a visual software display platform . First , according to the P - series propagation recommendations of the International Telecommunication Union (ITU-R), it combines with the actual geographic information to obtain the terrain and environmental data. Then, based on various different propagation paths, it uses the digital map model to establish the propagation models respectively to calculate the wave propagation loss and complete the design and implementation of the simulation calculation interface. Finally, it gives the height and frequency of the transmitting and receiving antenna and establishes the complete radio wave propagation model to perform simulation according to the actual terrain. The results illustrate that the algorithm model can not only obtain the loss of each position on the propagation path, but also have more sensitivity in different regions and terrains comparing with the traditional Hata calculation model. This model can effectively improve the calculation accuracy of propagation loss, and it is more suitable for calculating the wave propagation loss under the actual longdistance irregular and complex terrain, and helps to improve the communication quality effectively.