A method and a system for supporting a touch function on a terminal for performing a touch operation in which a writing pressure is applied to a touch pen of the system including the touch pen and a terminal are provided. The method includes touching a touch pen to a touch panel of the terminal, the touch pen having a capacitance that corresponds to and varies with pressure applied to the touch pen, generating, by the terminal, an instruction word corresponding to a result of adding the capacitance corresponding to the pressure applied to the touch pen when the touch pen is touched to the terminal and a capacitance of the touch panel, and performing a user function corresponding to the instruction word.