In recent years, with the continuous development of science and technology, the accuracy requirements for flow measurement are also constantly improving. The development of micro flow measurement technology plays a driving role in biomedicine, chemical engineering, semiconductor manufacturing and other fields. In this paper, the relationship between the fluid velocity in the pipe and its pressure on the pipe wall is used to sense the pressure wave generated by the fluid flowing through the pipe through the piezoelectric film, and then measure the small flow in the pipe. A pressure sensitive element was made of polyvinylidene fluoride (PVDF) piezoelectric film, and a real flow experimental platform was built. By processing the voltage signal with flow information collected from the real flow experiment, the voltage fluctuation amplitudes corresponding to 9 flow measurement points are obtained. The flow voltage amplitude characteristic curve is obtained through curve fitting, and the flow measurement sensitivity, relative error and repeatability are calculated. The real flow experiment results verify the feasibility of the micro flow measurement method based on pressure wave. The research of this method is an innovation of micro flow detection method, which has important practical significance.