The interface between the inclusion and the medium is not always perfect.That is,the displacement and stress are not continuous and equal on the boundary.The dynamic response of an incident P wave at an imperfect interface is different from the that of a perfect interface.A spring model is introduced as the imperfect interface model to calculate the dynamic response of the inclusion with an imperfect interface under the plane P wave incident.This interface model is assumed to be an elastic adhesive layer with an infinitesimal thickness and no inertia.Moreover,the wave function expansion method is used to calculate the dynamic stress concentration factor around the imperfect interface under the plane P wave incident and analyze the influence of spring stiffness,an important parameter of spring model,on the dynamic stress concentration factor.The results show that the spring stiffness has an obvious effect on the dynamic response with a low wave number,and this effect will gradually weaken with the increase of the wave number.At the same time,the resonance scattering phenomenon can be observed at a high wave number.The Ricker wavelet,a common seismic wavelet,is used as the transient disturbance waveform.Based on the steady-state results,the transient responses under different values of spring stiffness are obtained by Fourier transform.The distribution of the transient DSCF is similar to that under the steady-state conditions,but the amplitude has increased.In addition,the dominant frequency of the Ricker wavelet is negatively correlated with the transient DSCF.