The micro combustor is an important part of micro-thermophotovoltaic(MTPV) system, the outer wall temperature and its uniformity of combustor have an important influence on energy conversion efficiency of MTPV system. A new type of micro porous medium combustor was proposed in this study. The heat-transfer performance is improved by setting porous medium in micro combustor, and more heat circulates effectively. The combustion characteristics of H₂-CO-CH₄ non-premixed syngas in micro porous medium combustor were studied by numerical simulation. The effects of porous medium, fuel mass flow rate, equivalence ratio and external environment on outer wall temperature, center temperature and flame position of combustor were analyzed. The study results show that compared with free flame micro combustor, micro porous medium combustor has higher outer wall temperature and lower flame temperature. When the equivalence ratio is 1, the outer wall temperature of micro porous medium combustor reaches the peak. The relationship between the outer wall temperature and the convection heat-transfer coefficient presents a linear change rule.