Keeping exhaust gas temperature constant in oxygen enriched and flue gas circulating Micro Gas Turbine, Numerical Research is carried on to study inlet temperatures influence on combustion characteristics. Simulation shows that along with increase of methanes temperature, combustion efficiency increase slightly, uniformity coefficient of outlet temperature decreases, total pressure recovery coefficient decreases, content of carbon monoxide and methane in outlet gas decrease. However, when inlet methanes temperature exceed 100 °C, content of NOx increase rapidly in flue gas. The simulation result supplied reference for design of oxygen enriched and flue gas circulating combustor.