Memory device and operating method thereof

A memory device may include a plurality of memory cells; one or more backup memory cells; a test circuit suitable for performing a backup operation and a test operation to a test target cell selected among the plurality of memory cells; and a control circuit suitable for accessing the backup memory cells instead of the test target cell during the performance of the test operation after completion of the backup operation for the selected test target cell, wherein, during the backup operation, the test circuit controls the control circuit to copy an original data of the test target cell to a corresponding backup memory cell selected among the backup memory cells, and wherein, during the test operation, the test circuit determines whether the test target cell is a pass or a fail.