Abstract:The desirable approximate expression of P-SV wave refIection coefficient is deduced from the accurate solution of Zoeppritz's equation. Then,the reflection amplitude of P-SV wave is proved to be directly proportional to △Vs/Vs,where Vs is theaverage interval velocity of shear waves at the both sides of reflector,and △Vs is theinterval velocity difference of the shear waves.The horizontal stack of common conversion points of P-SV waves is changed into fitting stack of these comrnon conversion points to result in stacked amplitudes which are directly proportional to △Vs/Vs.People can obtain S-wave interval-velocity section by imitating wave impedancetechnique in P-wave exploration,namely,by rnaking downward layer by layer recursion inversion and calibration of fitting-stacked (or rnigrated) section of P-SVwaves.