Abstract: The generalized dispersion character equations of the guided waves in the piezoelectric coating composite structure with rigid, slip and weak interfaces are derived by combining the propagation model of the guided waves in layered piezoelectric composites structure and the interface 'spring' model. Numerical computations are made for dispersion characteristics of the guided waves in PZNT, a Pb(Zr, Ti)O3 based piezoelectric composite, coating composite structure with different interface conditions. The influence of the interfacial property on the phase velocity of the lower order guided wave modes is studied. Numerical analysis shows that it is very vital to select the corresponding ultrasonic mode and frequency in order to evaluate the interface property efficiently. The primary experimental results confirm the assumption of the interface property in this paper. The theory is promising to be explored to characterize the interfacial property of the piezoelectric coating composite structure.