The invention discloses a lighting and dimming circuit of a gear indicator of an automobile shifter. The lighting and dimming circuit comprises a brightness opening and closing circuit, a control power circuit, a driving and brightness adjusting circuit and a storage battery power supply +BATTERY, wherein the brightness opening and closing circuit comprises a photo-resistor RG2, an R5, an R18, an R19, an R20, a Q1 and a Q3; the control power circuit comprises a diode D3, a TVS tube D1, a voltage-regulator tube DT1 and a resistor R7; and the driving and brightness adjusting circuit comprises an operational amplifier IC1A, a triode Q1, a triode Q3, an MOSFET Q2, a photo-resistor RG1, a photo-resistor RG2, a potentiometer RK1, resistors R1, R2, R3, R4, R5, R6, R10, R18, R19 and R20 and a capacitor C3. According to the lighting and dimming circuit, backlight lighting of the gear indicator can be automatically opened or closed according to the bright and dark degree of the environment; the backlight brightness can be automatically or manually adjusted; the driving comfort, convenience and reliability are improved; for a plurality of vehicles free of lighting adjustment, an overall vehicle control logic does not need to be changed; and the functions, modification and the convenience thereof can be solely completed by the circuit.