The present invention discloses a method for processing cache data, which is used in a dual redundant server system having a console end and a redundant control end. The console end mirrors a cache data saved in the console end into a mirrored cache data and sends the mirrored cache data to the redundant control end through a transmission unit. If the console end determines that the redundant control end cannot save the mirrored cache data, the console end will flush the cache data into a hard disk installed at the console end.