Blood pressure monitoring device, system and method based on ultrasonic waves

The invention discloses a blood pressure monitoring device, system and method based on ultrasonic waves. The blood pressure monitoring device comprises a wearing part and a monitoring part, and the wearing part and the monitoring part are connected end to end to form a ring. Wherein the monitoring part comprises an ultrasonic transducer, a controller, a display and a power supply part. The ultrasonic transducer comprises a first ultrasonic transduction part and a second ultrasonic transduction part, the first ultrasonic transduction part is arranged in the first direction and emits first ultrasonic waves, and the second ultrasonic transduction part is arranged in the second direction and emits second ultrasonic waves. And the controller is electrically connected with the ultrasonic transducer so as to acquire the diameter and the type of the blood vessel based on the electric signal fed back by the first ultrasonic transduction part and acquire the blood flow rate based on the electric signal fed back by the