Novel ultrasonic fluid flowmeter and method for measuring flow rate of fluid

The invention discloses a novel ultrasonic fluid flowmeter and relates to the field of fluid flow measurement. The novel ultrasonic fluid flowmeter comprises a pipeline, an internal coating layer, anupper ultrasonic sensor and a lower ultrasonic sensor, wherein the internal coating layer is arranged on the inner wall of the pipeline, the upper ultrasonic sensor and the lower ultrasonic sensor arearranged on the upper side and the lower side of the pipeline respectively, and the upper ultrasonic sensor and the lower ultrasonic sensor are provided with an upper ultrasonic probe and a lower ultrasonic probe respectively. The upper ultrasonic sensor is connected with an electron-emitting circuit, and the lower ultrasonic sensor is connected with an electron-receiving circuit; an acoustic impedance layer is arranged between the upper ultrasonic probe and the internal coating layer, a matching layer is arranged between the lower ultrasonic probe and the internal coating layer, one end of the acoustic impedance laye