Abstract: A method and a device are used for switching a character input mode of a computer system. The character input mode switching device includes an input device, a display unit and an operating system unit. The input device includes a switching control element and a main control unit. The main control unit includes a switching module. An input signal is generated by the switching control element according to a single-step operation of a user and transmitted to the switching module. A switching signal is generated by the switching module after the input signal is received. The operating system unit judges whether the switching signal is an input language switching signal or an input method switching signal after the switching signal is received. According to the switching signal, the input language or the input method is switched by the operating system unit.