<p>Effects of the initial stress and imperfect interface on scattering of SH waves by the piezoelectric material cylinder embedded in an infinite elastic medium have been investigated in this article. The analytical expressions of the mechanical displacement, dynamic stress, electric potential, and electrical displacement are obtained using wave function expansion method. By simulating the imperfect interface with piezoelectric spring models, the effects of the initial stress and imperfect interface on the mechanical displacement, dynamic stress, electric potential, and electrical displacement around the interface between the piezoelectric material cylinder and elastic medium are discussed in detail. Numerical results show that there is no evident effect of the initial stress on the mechanical displacement, dynamic stress, electric potential, and electrical displacement of low frequency waves, these parameters decrease as the initial stress increases for high frequency waves. As the degree of the interface imperfection increases, the dynamic stress increases but the electric potential and electrical displacement decrease. The results obtained in the article are significant for designing high-performance piezoelectric acoustic wave devices.</p>