A method for managing function modules using a computing device. The computing device loads the function modules according to a serial number corresponding to a filename and a directory path of each function module. The computing device obtains register commands from an interface of each function module and saves the register commands into a command library. The computing device searches for a register command in the command library when the register command is inputted by an input device connected to the computing device, and executes the searched register command of the function module.