An operating method of a semiconductor memory device includes precharging a channel region of a program-inhibited cell of first memory cells coupled to a first word line, selected from a first one of word line groups between a drain select line and a source select line, to a first level based on first data; performing a first program operation for storing the first data in the first memory cells; precharging the channel region of a program-inhibited cell of second memory cells coupled to a second word line, selected from a second one of the word line groups, to a second level based on second data to be stored in the second memory cells; and performing a second program operation for storing the second data in the second memory cells.