Ultrasonic underwater sensor is mainly used for underwater robots, the product utilizes ultrasonic measurement principle, due to the inverse piezoelectric effect of ultrasonic waves, when propagated in the water, encountered obstacles after the reflection of the return wave, received by the sensor, the built-in circuitry for the digital conversion of the received signals, and through the MCU according to the principle of the obstacle TOF calculated distance. The protection level of the product reaches IP68, which can be immersed underwater for a long time, and the material is corrosion-resistant and not easy to be damaged.