This paper proposes a gas-liquid, double-acting traveling-wave thermoacoustic heat engine (GLDA-TWTHE), which has the advantages of both traditional thermoacoustic engine with long life span and the Stirling engine with high power density and high efficiency. By connecting three or four same thermoacoustic engines into a loop with a U-type liquid resonator, each engine can work in an ideal traveling-wave field, consequently bringing about high thermoacoustic conversion efficiency. We designed such an experimental system with about 3kW acoustical power. The GLDA-TWTHE consists of three same thermoacoustic heat engine units and three same U-type liquid-water columns with about a diameter of 50mm. The operating heating temperature, ambient temperature, and resonant frequency are 923K, 303K, and 25Hz, respectively. Before the experiment, numerical simulation on the GLDA-TWTHE under no-load and loaded conditions was made for providing a theoretical prediction. Also, we have analyzed the influence of some parameters of the three engines being inconsistent with each other on the system performance. Finally, the experimental results were compared with the simulation, showing good agreement with each other. Based on both the theoretical and experimental results, it is found that the novel GLDA-TWTHE is a very enabling technology due to its high reliability, simple structure, and high efficiency. Copyright (c) 2013 John Wiley & Sons, Ltd.