Abstract: A bilevel hybrid topological layout optimization model for oil-gas gathering and transferring system was established,in which the minimal pipeline length was taken as the objective function,and the unique memberships,the processing capacity and geometrical position of nodes were taken as the constraint conditions.The model concerns the hybrid optimization design problem with disperse and continuous variables.According to the configuration characteristics of the model,the optimization problem was divided into location and allocation layers,and solved by hybrid genetic simulated annealing algorithm.In order to improve the optimization performance,the chromosome was coded in real number,while free crossover and dominating crossover were combined with each other,and subtle mutation and violent mutation were alternated.The reproduction strategy based on Metropolis criteria and elitist preserved strategy were also applied.Practical example indicated the accuracy of the optimization model and feasibility of the algorithm.