1. A recovering method, adapted to an encoding operation performed on a storage area of a storage device, the recovering method comprising: reading a variable set, wherein the encoding operation comprises a plurality of sub-operations, and each of the sub-operations is corresponding to at least one flag variable in the variable set; determining whether any one of the sub-operations is interrupted according to the variable set; when one of the sub-operations is interrupted, recovering the sub-operation according to the at least one flag variable corresponding to the sub-operation; and carrying on the encoding operation according to a process recorded by the flag variables in the variable set.