Excess enthalpy combustion characteristics of low heating value gas were numerically investigated in a novel model of reciprocal porous media combustion system with heat recirculation.Based on the comparison of the model with the experimental results，the effective of the model was verified，and the mechanism of excess enthalpy combustion in the system was clarified.The influence of the conditional and material characteristic parameters on the excess enthalpy characteristics were analyzed including half period，heating value，secondary air ratio，heat capacity ratio，optical thickness，convective coefficient etc.The excess enthalpy combustion can be obtained in the system when the dimensionless heating value is no more than 3.48.The lower the heating value，the higher the level of the excess enthalpy is.The results also showed that the combustion efficiency was seldom influenced by those parameters and kept a high level at the steady combustion state，which further proved the high effectiveness of porous media combustion