Electromagnetic ultrasonic sensor

The utility model provides an electromagnetic ultrasonic sensor which comprises a magnet assembly, a hollow coil and a shell, the magnet assembly comprises a first magnet and a second magnet, the second magnet and the first magnet are coaxially arranged, the first magnet is sleeved with the second magnet, and the magnetic field directions of the first magnet and the second magnet are opposite; the hollow coil is arranged below the magnet assembly, the hollow coil and the magnet assembly are coaxially arranged, the inner diameter of the hollow coil is smaller than the outer diameter of the first magnet, and the outer diameter of the hollow coil is larger than the inner diameter of the second magnet; the shell is arranged outside the magnet assembly and the hollow coil in a sleeving mode, the shell is provided with a plug-in port, and the plug-in port is electrically connected with the hollow coil. The coil of the sensor provided by the utility model stretches across the two magnetic poles, so that the strength