Multi-stage time synchronizing system

The utility model provides a multi-stage time synchronizing system mainly including a second-stage time server and a third-stage time server. The second-stage time server mainly receives PTP signals sent by a main clock for time synchronization and sends the PTP signals to the three-stage time server. The third-stage timer server receivers the PTP signals sent from the second-stage time server for time synchronization. The second-stage time server includes a boundary clock, a synchronous digital hierarchy algorithm module and a PTP output port. The synchronous digital hierarchy algorithm module is used for tracking and synchronizing PTP signals from a synchronous digital hierarchy network accurately and stably. The boundary clock is used for supplementing and correcting the PTP signals received from the main clock by the synchronous digital hierarchy algorithm module by utilizing pulse per second generated when upstream signals are synchronized to the main clock in the second-stage timer server and sending new PTP signals generated after the supplementation and correction to the PTP output port. The PTP output port sends the PTP signals to the third-stage time server.