Recently, combustible waste has increased significantly as the industry developed, and most of these wastes are treated by thermochemical treatment methods. Among the various thermochemical methods, the most typical method is an incineration technology utilizing a combustion reaction, However, incineration technology has been fundamentally applied for the purpose of safe treatment rather than energy recovery. So, gasification research has been studied to improve the efficiency of energy recovery. The technology of waste gasification is basically based on coal gasification technology. Therefore, in this study, a thermochemical equilibrium modeling for waste gasification reactions has been studied by using the previous study on the characteristics of the coal gasification. And in order to verify the feasibility of the thermochemical reaction equilibrium model applied in this study, a comparisons with the field results were also performed.