Abstract: Well logging technique with P and S wave is one of seismic exploration methods.It is an easy,rapid and accurate method of in situ measurement.Through measuring elastic wave velocity of rock and soil layers with P and S wave well logging technique,we can supply elastic dynamic parameters for engineering design,plot out the site grade of building,evaluate earthquake's effcet,analyze site earthquake response and potential damages.The working principles,field observing techniques,data processing and analysis about P and S wave well logging technique are briefly introduced.In the end we illustrated the application of P and S wave well logging method and its effect in geotechnical engineering investigation and design with two practical examples.