Abstract: An ultrasonic spray coating system includes a piezoelectric transducer, a spray-forming head and a liquid supply applicator. The spray-forming head has an air-entrainment mechanism. The air-entrainment mechanism has an air-stream channel that is formed inside a main body and a bottom body of the spray-forming head for connection with a high-pressure air source, and an air vent formed in a bottom surface of the bottom body and communicates with the air-stream channel. A length of the air vent in a horizontal direction is greater than that of the air-stream channel. The liquid supply applicator has a discharge orifice, and a control component for controlling the size of the discharge orifice.