In this paper, is proposed a calculating method for the simulation of oscillatory combustion state, and comparisons between estimation results and experimental ones are carried out. With respect to the effects of geometric dimensions of combustion system, and of fueland air-flow rate conditions on characteristics such as an amplitude of oscillation, its fluctuation, and a frequency, a theoretical analysis presents a correct estimation of the phenomena. By use of this analysis, it becomes possible exactly to estimate the changes which take place in the combustion system. On the basis of the quantitative feature of the theoretical results, the influences of the factors such as ignition lag, wall temperature ratio, and heat transmission on the combustion oscillation are studied.