Abstract: During the start-up, shutdown and load change of the unit, the coordinated control of the high, medium and low pressure bypass valves of the steam turbine is prone to problems such as response lag and excessive pressure fluctuation. To address the above challenges, this study proposes a coordinated control scheme for high, medium and low pressure bypass valves based on DCS from both hardware design and software design aspects. The experimental results show that this scheme can significantly reduce the pressure overshoot and fluctuation amplitude, accelerate the response speed, and improve the stability and economy of the unit under complex working conditions.