A memory system may include: a memory device including a plurality of memory blocks each having a plurality of sub memory blocks; and a controller suitable for performing an error correction operation to the memory blocks during a read operation to the memory blocks, updating a characteristic list for the memory blocks at each error correction operation to the memory blocks, classifying the memory blocks and the sub memory blocks according to the updated values in the characteristic list, and performing a program operation to the memory blocks according to the classification.