The invention relates to an electromagnetic ultrasonic transducer and a test system, and belongs to the technical field of nondestructive testing. The electromagnetic ultrasonic transducer comprises ashell, and an amplifying device, a receiving and transmitting device and a magnet which are arranged in the shell, wherein a magnetic leakage window is arranged in a first surface of the shell; a non-metallic material plate is arranged at the magnetic leakage window in order to close the magnetic leakage window; the receiving and transmitting device is arranged at the magnetic leakage window; themagnet is located between the amplifying device and the receiving and transmitting device; the amplifying device and the magnet are attached to each other; the amplifying device is connected to the receiving and transmitting device; a wire outlet hole, a water outlet hole and a water inlet hole are arranged in a second surface of the shell; and the amplifying device is connected to a signal wireleading out of the wire outlet hole. A tested piece is tested, circulating cooling water is injected into the shell through the water outlet hole and the water inlet hole, and then the temperature inside the shell is maintained, a problem of high-temperature cooling of metal material detection under a red heat state is solved, the effective existence of the magnetic field of the magnet is guaranteed, and the sensitivity and the accuracy of reception of a defect signal are ensured.