For parameter design of xerographic process with simulation, suitable simulation models have to be established. Thermal control design of a complex fusing system requires a simulation tool not only with high accuracy but also with high speed. The simulation model developed in this study utilizes hybrid calculation technique of one and two dimensional heat transfer model and is capable of high speed calculation without losing accuracy. In this model, heat transfer efficiencies between components are defined and determined by one dimensional numerical analysis in prior. The simulation tool for belt roll fuser installed in Fuji Xerox Color 1000/800 Press was developed and applied to parameter design. As a result of the application, time required for the development was largely reduced.