Abstract: An anti-EMI ultrasonic transducer has a conductive casing, a piezoelectric ceramic board having an opening, a conductive shelter, a first and second wires and an encapsulation. A first electrode face of the piezoelectric ceramic board faces to the opening and a second electrode face is mounted inside the conductive casing. The conductive shelter is mounted inside the conductive casing or covered to the opening, so the piezoelectric ceramic board is encapsulated in the conductive shelter and the conductive casing. Since the second signal wire is connected to the conductive shelter mounted inside the conductive casing, the conductive shelter and the conductive casing and the second electrode face of the piezoelectric ceramic board are commonly electronically connected to a voltage signal transmitted by the second signal wire. Therefore, the conductive shelter and the conductive casing are constituted to an EMI shelter for the piezoelectric ceramic board to resist external EMI signal.