The invention relates to an application method of a hand-held ultrasonic measurement channel flow velocity apparatus, is applied to flow velocity measurement of a channel, and belongs to the technical field of flow velocity measurement of a river course or channel. The technical scheme is as follows: measuring flow velocity data is received by use of an intelligent mobile phone in a wireless mode, application software is installed on the intelligent mobile phone, necessary measurement point onsite data is input through the application software, the application software automatically generates a test scheme, an operation prompt is given to a measurer in a measurement process, a currently operating test point is displayed, the flow velocity data is further processed, flow information is finally generated, at the same time, the geographical position of the test point is displayed, and anyone can conveniently carry out operation skillfully. The advantages are as follows: the measurement process of the hand-held ultrasonic measurement channel flow velocity apparatus is enabled to be converted into fool-style operation from conventional complex operation implemented by professionals; and the popularity rate of the intelligent mobile phone is quite high, anyone can conveniently carry out the operation skillfully without professional technical knowledge, and promotion and application are facilitated.