Abstract: The ultrasonic nondestructive testing method based on the PVDF piezoelectric film sensor was introduced. Firstly, the mechanism and element of the PVDF piezoelectric film sensor were illuminated in detail, and the signal processing circuit was designed according to the signal feature. Secondly, the ultrasonic nondestructive testing system based on the ultrasonoscope and PVDF piezoelectric film sensor was built. At last, the method was verified through the detection of aluminum specimen. The results show that the detection signal through the method has a high SNR, and it can locate the internal flaw of specimen exactly, and is suitable for flaw detection.