In this paper, experimental and numerical methods were used to study the combustion characteristics of a counter-rotating double-stage swirling syngas combustor at constant fuel flow rate, and the effect on it of hydrogen content of syngas. In the experiment, the speed and temperature in the combustor were respectively obtained with Ply and temperature rake, while Reynolds stress equation model and the detailed chemical reaction mechanism of syngas were adopted in the numerical method. The calculation results were in good agreement with the experimental data. Research results indicated that in the working conditions of different hydrogen contents, the flow field structures in the combustor are almost the same, and the maximum temperatures at the outlet remain almost the same. However, as hydrogen content in the fuel increases, the axial velocity in the central area of flow field is increasing, and the outlet temperature distribution coefficient decreases first and then increases. In addition, it was also found in the study that the distribution structure of temperature on the central section of the combustor is almost impervious to the changes in hydrogen content, but with numerical differences, i.e. the higher hydrogen content in the fuel, the farther the stabilization position of flames in the central area is away from the head. It was also indicated in the study that the conventional combustor is no longer applicable to the combustion of syngas, especially the hydrogen rich fuel. And the work provided the improvement scheme of hydrogen-containing fuel for gas turbine combustor. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.