In order to eliminate pollution from ultra low calorific value gas (ULCVG) of methane and achieve energy recovery simultaneously, a novel reactor with the function of regenerator and catalytic combustor named rotary regenerative type catalytic combustion reactor is studied. The reactor walls which store and reject heat alternatively can preheat incoming ULCVG to the ignition temperature of methane, and catalytic combustion occurs rapidly. According to the features of the reactor such as rotation and catalytic combustion, considering the conjugate heat exchange, the characteristics of this reactor were calculated and analyzed with the help of computational fluid dynamics (CFD). The results show that the ULCVG can be oxidized as a primary fuel, with the methane conversion above 91%, and the feasibility of this reactor is proved in theory. The reactor can continuously generate high-temperature gas (1035 K–1200 K) which can be used by the heat consumption unit (HCU) such as turbines, boilers, and solid oxide fuel cell services. Besides, the outlet gas and exhaust gas temperature vary roughly linearly with time, and this rule is useful to estimate the outlet temperature. Periodical rotation not only provides high-temperature zone which is beneficial to catalytic combustion, but also avoids further heat accumulation.