External clip type ultrasonic flowmeter is composed of a main body and an external clip type sensor. Simply attach the clip-on sensor to the surface of the pipe to complete the flow measurement of various liquids. Compared with the traditional flow meter, it does not need to cut off the tube, and the installation is quick and convenient, realizing the non-destructive installation. The main unit can be installed in the wall, instrument box and distribution box, and the protection level can reach IP67. The external clip type sensor is installed on the surface of the pipe, and different sensors are selected. The applicable diameter is DN15~DN6000.