Underground gas pipeline leaks can lead to tremendous economic loss and human injury. Therefore, it is vital to detect and locate the pipeline leaks in time to maintain the normal operation. However, continuous leak-detection methods of require a lot of manpower, marterial resources and financial supports, while other detecting activities, break the normal operation of the pipeline. Hybrid techniques consisting of two or more different technologies appear to be the most probable future trend in pipeline leak detection and location field. In this paper, a novel hybrid technique based on real-time transient modeling method and negative pressure wave method is proposed. An experimental bench for straight pipelines is set up to evaluate the performance of the proposed hybrid technique, and corresponding experimental test programs for gas leak detection and location are designed and conducted. A mathematical model for the transient flow in pipelines has been established and solved under different boundary conditions. The occurrence of a leak can be preliminarily judged by the difference between the measured data and the predicted value from the model; and the changing patterns of parameters under the leak condition, the valve-opening adjusting condition and the compressor-speed regulating condition are investigated to identify the leak condition out of the operational changes. Finally, the leak point is located using the stimulus-response method. Results show that the hybrid technique is successful in detecting and locating gas pipeline leaks. It is expected that the research outcomes can serve as a technical base for the safe operation of gas supply networks. (C) 2015 Elsevier Ltd. All rights reserved.