An operating method of a memory system includes determining that a map management operation is triggered, based on physical-to-logical (P2L) entries generated after a previous map management operation is completed, wherein the P2L entries respectively correspond to physical addresses of a memory region of a storage medium; generating a pre-update table corresponding to the memory region based on the P2L entries regardless of whether a write operation of the storage medium is completed; updating L2P entries based on the P2L entries after the write operation is completed; and generating, a new original update table by merging the pre-update table and an original update table corresponding to the memory region when the original update table is present in the storage medium and generating, after the L2P entries are updated, the pre-update table as the new original update table when the original update table is not present in the storage medium.