A method for backing up power failure for an automatic medicine packing machine includes steps of creating backup file from prescription data, storing backup file, deleting backup file for which packing of corresponding medicine is completed, detecting power recovery, and performing backup operation. In the step of creating backup file, when prescription data are received, the prescription data are arranged in preparation order and classified into one or more packing units, and a backup file is created for each of the packing units. An apparatus for the method includes a controller, a storage unit that stores backup files and a power recovery detecting unit that detects power recovery after power failure.