Abstract：When shocked by strong stress,the medium near seismic sourc showsplastic property instead of elastic property.Big error occurs when.such plastic strain is simplified as the linear function of displacement.On the basis of plasticity theory，authors put forward the mathematicalmodel of seismic wave in plastic medium, describe the relevant solvingmethod and derive plastic wave field using numerical modeling, Con-ventional acoustic wave model，elastic wave model and elastoplastic wavemodel can be considered as the special cases of plastic wave model.Numerical modeling result proves that plastic wave . model shows moreseismic wave properties than others do.
