Provided herein is a semiconductor memory device and an operating method thereof. The semiconductor memory device may include a memory cell array, a peripheral circuit, and a control logic. The memory cell array may include a plurality of memory blocks. The peripheral circuit may perform a program operation or read operation on a selected memory block of the memory cell array. The control logic may select between a first program method and a second program method depending on program mode information for the selected memory block, and may control the peripheral circuit to perform the program operation on the selected memory block using the selected program method.