The design of PVDF transducer is finished and its designing idea and structure frame are presented. The laser ultrasound in nano A1P/SiO2 is detected by the PVDF transducer and the acoustic signal curve is obtained. The ultrasound waveform thermal elastically generated by a rectangular laser pulse is theoretically presented. The ultrasound pulse waveform obtained in the experiment is in accordance with the one in theory. It is shown that this design method is simple, practical and easy to implement.