In this study a dynamic model Simulation was carried out using ASPEN HYSY for industrial refinery fired heater, PID controller was applied to control the flue gas exit temperature. the simulation shows perfect agreement with the datasheet of the furnace. It was found that Increasing the number of the tube rows in convection bank from 2 to 3 allows us to recover approximately 5% of the overall efficiency, hence the duty furnace has increased from 65.9MW to 68.1MW and the fuel flow in like manner has increased from 5597kg/h to 5807kg/h moreover Adding more rows has a reverse return as we start to notice increase on the flue gas temperature. Furthermore, sensitivity analysis was conducted with HYSYS to determine one of the most important parameters that affect the performance of the heater based on the data generated from the simulation. MATLAB code was generated for efficiency calculation and for parameter manipulation, the code was designed to be flexible as possible, user will just need to replace the nominal fuel and air characteristics. for gaining optimum furnace operation the heat transfer inside the furnace was studied, and the results were compared with previous research involving furnace analysis to validate models, the heat transfer coefficient is determined by analysis of conductive heat transfer through the boundary layer. well-stirred model was used for mathematical model calculations and for optimization of furnace operation, the models were validated with ASPEN Exchanger Design and Rating(EDR) alongside ASPEN HYSYS