Abstract: Taking the 600 MW supercritical steam turbine as an object of study, a theoretical analysis was conducted on the energy saving potential of the composite regulation mode, while experimental tests were performed to determine the flow characteristics, analyze the energy consumption characteristics and to set the overlap degree of various high-pressure control valves under different sequences of operation, following which, the sequence of valve opening was optimized. Results show that after optimization, the high-pressure cylinder efficiency could be increased by 1.53%, 1.34% and 1.42%, and the corresponding heat consumption rate could be reduced by 26.0 kJ/(kW·h), 23.2 kJ/(kW·h), and 25.3 kJ/(kW·h), respectively at the medium/low loads of 500 MW, 400 MW and 330 MW.