An on-the-fly error checking and correcting system and method of supporting a non-volatile memory processes data using an on-the-fly error correction method to be performed between a temporary memory and a flash memory. The flash memory stores actual data read from the temporary memory and parity generated on-the-fly in a write mode, and transmits the stored data to the temporary memory, computes a syndrome from the stored data on-the-fly, and generates an error correction information signal according to the result of computing in a read mode. Thus, error correction may only be selectively performed.