Abstract:AVO phenomenon of seismic reflection waves can be seen in both P wave and P-SV wave.Under some conditions,P-SV wave may show more obvious AVO phenomenon than P wave.AVO characteristics of P-SV waves from top and bottom of gas-bearing sandstone has been analysed with the use of Zoeppritz equation and related petrophysical parameters.Having converted seismic data from x-t domain to θ-x domain by ray tracing method,we can see very obvious amplitude-variation difference between gas-bearing and gas free parts of the same horizon.Besides,the section of envelope difference shows obvious amplitude anomaly along the periphery of gas reservoir.We can thus discover hydrocarbon accumulation by analysing the AVO characteristics of P-SV wave in an area.