High temperature air combustion technology uses a high- cycle regenerative heat exchanger for preheating the furnace air to above 1000 degreesC, much higher than in conventional furnaces, and then fuel is injected into the air. This technology has found many practical applications in a variety of industrial furnaces. All investigations and discussions hitherto have focused on the steady-state condition, but in view of variations in the cycle time, and the fact that ejection of fuel and air, diffusion, mixing, ignition and combustion occur continuously and repeatedly, non-steady state and unstable phenomena can be expected. Ii the system is in an unsteady state, then it must be considered in a different way. Here, this problem is discussed based on combustion analysis results. High temperature air combustion flame has a wide spatial distribution of gas, and then that analysis should be implemented by utilizing the concept of a uniformly stirred reactor. Here we analyzed the test data using plug-flow type and well-stirred type reactors for a combustion exothermic model.