Brightness regulating method

The invention relates to a brightness regulating method. By a brightening circuit and a dimming circuit which are connected with an X86 computer platform processor U1, the platform processor U1 is directly controlled; a brightening key Key1 and an electrostatic protection diode D1 in the brightening circuit are connected and are connected to a pin GPIOx of the X86 platform processor U1 by a first filter circuit, so as to wholly form a regulating circuit for an external backlight brightening instruction; a dimming key Key2 and an electrostatic protection diode D2 in the dimming circuit are connected and are connected to a pin GPIOy of the X86 platform processor U1 by a second filter circuit formed by a resistor R3 and a capacitor C2, so as to wholly form a regulating circuit for an external backlight dimming instruction. By adopting the method, the functions of receiving brightness regulating instructions of a user and outputting pulse width regulatory signals are realized by combining a simpler external circuit with an X86 platform controller, IC (Integrated Circuit) communication delay with a third party is avoided, the problem of insensitive reaction to the regulating instructions is solved, and the power consumption and cost are reduced.