The present invention provides a method of decreasing program disturb in memory cells, comprising: finding an initial programming condition that ensure programming memory cell normally; selecting one parameter from the initial programming condition as a variable for the program disturb test; performing the program disturb test to the memory cell for at least two values of the variable; obtaining a programming condition with minimum program disturb based on the result of the program disturb test; and applying the programming condition with minimum program disturb as the programming condition for memory cell. The method according to the present invention can minimize the program disturb for the memory cell and can be performed easily.