The invention discloses an online synchronized method of a distributed real-time database confronting a power system. The distributed real-time database in the method at least comprises a real-time state and a test state. The online synchronized method in the invention comprises the following steps: forming incremental files when data in the database need to be modified; testing the incremental files under the test state firstly; after passing through verification under the test state, acquiring the incremental files by each node under the real-time state; completing incremental entry of the real-time database according to incremental marks and positions of incremental files; forming synchronized marks after completing incremental entry; and reinitializing programs by each real-time database application programs under the real-time state and completing the whole synchronized flow. The data synchronization in the invention adopts an incremental mode, thus greatly facilitating the entryoperation of integrated system maintenance data and reducing impact on the network and the real-time database brought about in the entry process.