The invention discloses an ultrasonic wave flowmeter. The ultrasonic wave flowmeter comprises three pairs of ultrasonic wave transceiving devices which are arranged around circumference of a gas pipeline, wherein an ultrasonic wave propagation route formed by one pair of the ultrasonic wave transceiving devices is intersected with a center line of the gas pipeline, and ultrasonic wave propagation routes formed by the other two pairs of ultrasonic wave transceiving devices are parallel, and are symmetrically distributed on two sides of the center line of the gas pipeline; the included angle between the ultrasonic wave propagation route formed by each pair of ultrasonic wave transceiving devices and the center line of the gas pipeline is 30-60 DEG; and the two parallel ultrasonic wave propagation routes are located on the same plane, and the propagation route of the other pair of ultrasonic wave transceiving devices only has one insertion point with the plane. According to the invention, measurement accuracy is high; equipment stability is high; maintenance cost is low; and a fault self-diagnosis function and various data remote-transmission functions are integrated, so that a gas company can conduct real-time monitoring of states of a natural gas pipe network, conduct remote management of gas conveying and distribution, and make a timely response to abnormal states.