Abstract: The fuel oil system of heaters used in Guyi Oil Production Complex in Gudao Oilfield had to operate at constant pressure when supplying the fuel oil. The fluctuation of pressure of fuel oil supplying system will be taken place when the heaters had to be started up or stopped under the condition of technical requirements, which probably result in flash back or stop of burner. To keep the fuel oil system of heater operating at the constant pressure, the solutions (optimal design) are taken like variable frequency technique, changing the transient supply of fuel oil and simplifying the process flow, which realize the constant pressure operating of fuel oil system for heaters.