The invention discloses a high-reliability time calibration method of a relay protection device for a communication manager. The method comprises steps that (a), synchronization and loss of synchronism of a GPS device connected in a communication manager station are detected, and the synchronization and loss of synchronism states are uploaded and scheduled through remote communication shift; (b), preference strategies for GPS time calibration and scheduling network time calibration are set; (c), main and standby states of the communication manager are determined; (d), according to the time calibration strategies, a time calibration command is issued to the relay protection device. Operation states of devices in a power substation are mastered, through report analysis between scheduling and communication managers, whether the communication managers are main or standby ones can be determined. According to the method, the new time calibration strategy is employed, time calibration on the relay protection device can be carried out only when the communication manager is used as the main one for message scheduling and time calibration or GPS device synchronization in the power substation can be realized for time calibration on the communication manager.