Abstract: The in-line automatic seeking control strategy for the heat efficiency of heat medium heater depends on the thermal equilibrium of heating oil flow control system and the heat efficiency of in-line automatic seeking air-regulating system. The paper analyzes the control principle of the inline automatic seeking optimal system and presents the operating condition of heater as well as the optimal control procedure block diagram. The article considers that the system has a stable performance, high heat efficiency, and easy to care.