Abstract: As an important part of the comprehensive emergency support system,wireless emergency communication has incomparable convenience and economy in dealing with natural disasters such as flood,earthquake and tsunami.As the key link of wireless relay network,the location of relay node will directly affect the performance of the whole emergency communication network.The site of wireless emergency communication relay node in complex environment depends on field investigation and measurement,but there could be some problems,such as poor speed of siting,redundant relay nodes and poor communication link quality.Aiming at these existed problems,the propagation path loss between nodes is used as the basis to evaluate the quality of nodes.Based on the modeling and simulation of ray tracing method,the algorithm is studied to realize the fast and accurate siting of wireless emergency relay nodes in complex environment.The effectiveness of the proposed method is verified in the comparative experiment with the traditional siting method.

Key words: Emergency communication, Ray tracing, Path loss, Relay network, Dijkstra Algorithm