The invention provides discloses a method for data synchronization in a content delivery network. The method includes: a data synchronization client requesting a data synchronization processing manager for obtaining a belonged data synchronization processing agent, establishing a heartbeat connection with the belonged synchronization processing agent to acquire operation status of the belonged data synchronization processing agent; and the data synchronization processing manager scanning a management side database, and if a synchronization task needing to be informed to the data synchronization client is scanned in the management side database, the data synchronization processing manager generating the synchronization task for the corresponding synchronization processing agent in an ability side database. The present invention also provides a system for data synchronization in a content delivery network, a data synchronization processing agent and a data synchronization processing manager.