Abstract: The steady flow field and chemical reactions in a duel-chamber regenerative thermal oxidizer (RTO) were studied with the CFX software. Flow circumstances in the duel-chamber RTO were described by numerical simulation. Some influencing factors such as combustion temperature, the mass concentration of volatile organic compounds (VOC) and the mass fraction of oxygen, which affect the VOC destruction and removal efficiency of the duel-chamber RTO, were revealed quantitatively. The simulation results show that combustion temperature is the most important factor which directly affects the destruction and removal efficiency of the duel-chamber RTO, the inlet temperature of waste gas and the mass concentration of VOC influence indirectly by changing the combustion temperature, but the mass fraction of oxygen which is more than 0.03 has little effect on it. Based on the numerical results, a duel-chamber RTO was design, and an anticipated effect was achieved in applications.