Abstract: The present disclosure relates to a database (DB) synchronization apparatus of a transmission network system which includes a plurality of network elements (NEs) and an Element Management System (EMS). Each of the NEs may include a common memory in which DB information and alarm state information are rearranged and a sync-related memory of the same pattern as the common memory for maintaining DB identity with the EMS. The EMS may include a EMS sync-related memory for storing the DB and the information of the sync-related memory of the plurality of NEs, and a EMS common memory corresponding to the common memory (CM) of the NE. A common memory which reflects database information and the current alarm information to the NEs, and a sync-related memory which stores data prior to a T-second period are built on the NEs, and these two memories are compared in block units to thereafter transmit only modified block data to the EMS.