A method of reading multi-bit data stored in a memory cell of a flash memory includes attempting to perform hard decision (HD) decoding on output data from the flash memory, and performing soft decision (SD) decoding on the output data when the HD decoding cannot be performed. The performing of the SD decoding includes: changing a maximum number of iterations according to a threshold voltage distribution of the memory cell; and performing the SD decoding based on the changed maximum number of iterations.