The invention provides a control protection method for a flexible direct current power transmission system. A running state of an alternating current system is determined through a method combining alternating current voltage detection and alternating current frequency detection; and a running mode for enabling a flexible direct current system to be matched with actions of an alternating current system is determined. The control protection method comprises a high voltage power transmission system control protection method and a low voltage power transmission system control protection method; the control protection method is applicable to all existing alternating current systems; the matching time of the control protection system is greatly reduced; the power supply reliability of the system is improved; and the utilization rate of the flexible direct current power transmission system is ensured to the maximum.