Abstract: An operating method of a non-volatile memory device, the method including: receiving a program command from an external device; determining an operating mode in response to the program command; when the operating mode is a surface mount technology (SMT) mode, performing an initial program operation in which a plurality of memory cells are programmed through a plurality of steps to form a first threshold voltage distribution; and when the operating mode is a normal mode, performing a normal program operation in which the plurality of memory cells are programmed through a single step to form a second threshold voltage distribution, wherein the first threshold voltage distribution is narrower in width than the second threshold voltage distribution.