Explosion characteristics of syngas/air mixtures was investigated numerically in a 3-D cylindrical geometric model, using ANSYS Fluent. The results showed that the maximum explosion pressure increased from lean to an equivalence ratio of 1.2, then decreased significantly with richer mixtures, indicating that maximum explosion pressure occurred at the equivalence ratio of 1.2, while explosion time was shortest at an equivalence ratio of 1.6. Increasing H₂ content in the fuel blends raised maximum explosion pressure and significantly shortened the explosion time. Normalized peak pressure was sensitive to the initial pressure of the mixture, showing that they significantly changed with increased initial pressure.