Based on the theories and methods of operations research, a mathematical model for the shortest rescue route during gas leak emergencies in high-sulfur oil and gas fields is built in this paper, which contains two weights of rescue route optimization, and serves the bi-objective optimization process. An approximate search algorithm with two optimization objectives is proposed for the model based on heuristic algorithm, which could find out the shortest escape route from the double-weight escape route network by constructing auxiliary functions. Along with the study case of the gas leak emergency rescue system of the Puguang gas field in Sichuan, the algorithm procedures are introduced, the convergence rate of the algorithm are analyzed, and the time complexity and the strengths of the algorithm are discussed. By this algorithm, decision makers can find out the optimum rescue route on the distribution sketch map of the Puguang gas field, thus realizing the two optimizing targets, and providing strong technical support for gas leak rescue in the gas field.