Interstage turbine combustors can be used to improve the thrust-to-weight ratio of gas turbines, but their operating conditions and technical requirements are obviously different from those of traditional gas turbine combustors. A typical feature of these combustors is the slight temperature rise combustion under the high velocity conditions of combustor inlets. In this study, a new type of interstage turbine combustor with high performance was proposed, and the influence of the injection mode on the combustion characteristics was investigated. Seven combustion modes with a trapped-vortex combustion zone and preheated fuel nozzles were designed. The effects of the average temperature of the combustion zone (changed by the air injection mode) and the combustion-zone temperature distribution (changed by the combustion-zone configuration) on the combustion characteristics, including the stable combustion boundary, the combustion efficiency, and the temperature distribution, were studied experimentally and numerically. The results showed that high-efficiency combustion in a wide, stable working range was achieved. The new combustor had a shorter length than the conventional combustor and had a wider lean blowout boundary compared to the same type of combustor. Based on the results, the optimal combustor configuration that could be used for practical applications in high-efficiency gas turbines was determined. (C) 2019 Elsevier Ltd. All rights reserved.