In response to the frequent occurrence of liquid oxygen leakage accidents in domestic factories, improper emergency handling of workers and unsafe escape routes, an improved A* algorithm that pays more attention to safety and efficiency is proposed and embedded in the emergency drill system. By adding the weight factor and direction factor to the heuristic function, the A* algorithm can be better applied to complex addresses. At the same time, the safety distance of the waypoint is judged according to the calculation of the risk model to ensure the safety of the wayfinding route. Comparative experiment results show that in the path obtained by the standard A* algorithm, more waypoints are in the liquid oxygen leakage danger zone; the number of waypoints obtained by the improved A* algorithm with only modified heuristic function is less than the number of waypoints obtained by the first set of experiments and is faster approaching to the target point but there are still many waypoints in the dangerous zone; The waypoints obtained by the improved A* algorithm that both modify the heuristic function and consider the risk model are all outside the dangerous area of liquid oxygen leakage. It can be seen that the path obtained by the improved A* algorithm is safer and faster to converge to the target point than the standard A* algorithm.