The invention provides an automatic dust removal control circuit of an air conditioner. The control circuit comprises a resistor R1 (1), an NPN type triode Q1 (2), a relay RL1 (3), a light-emitting diode LED1 (4), an N-channel MOSFET Q2 (5), a motor M1 (6), a resistor R2 (7), a resistor R3 (8), an electrolytic capacitor C1 (9), a PNP type triode Q3 (10), and a light sensing sensor VT1 (11). According to the circuit, when external air enters the air conditioner, the detection is carried out, under the condition of more dust, the light sensing sensor VT1 (11) is cut-off, the NPN type triode Q1 (2) is switched on, the relay RL1 (3) is power-on and pick-up, a dust shielding plate closes, and an electromagnetic valve is pick-up; the dust shielding plate is closed to isolate the external dust from entering; when the amount of dust is reduced to a certain degree, the light sensing sensor VT1 (11) is switched-on, the motor M1 (6) rotates in 2 seconds or within to drive a dust suction fan to rotate, the air in the air conditioner is further sucked away, so that the indoor ventilation is guaranteed, and the amount of dust flowing into a room through the air conditioner is reduced.