Abstract: The fault of steam turbine bypass drain valve in the use process is analyzed. The remote mounting intelligent positioner is used to replace the original mechanical positioner and electric pneumatic converter. The impact on the steam turbine bypass drain valve due to in-situ vibration and high temperature is reduced. ValveLink software self tuning and fault analysis is adopted to test the valve after the completion of installation. The valve positioner parameters is optimized to solve the oscillation problem occurred in the valve adjustment. Through the use of isolation module, the independent power supply to handling the control circuit load problems are solved. The control stability and the safety of the turbine bypass valve is improved.