The invention discloses a turbine control valve quick-closing system control method based on fault critical mute time. On the basis of original triggering logic for a turbine control valve quick-closing function, judgment of power system fault types and selection of delay time are added. Turbine control valve quick-closing function triggering conditions under different faults are determined through analogue simulation of transient faults of a power system, and thus the optimum control valve quick-closing action delay time of different power generators under the active power (a per-unit value)is determined through analogue simulation of three-phase short troubles of the power system and according to fault critical mute time and power plant earth fault current disappearing time. By adoptionof the control method, fluctuation of transient abnormal power signals can be shielded, adverse effects on safe operation of a unit caused by delay during unit sudden load change can also be avoided,and safety and stability of the power system are effectively guaranteed.