Based on two sets of approximate equations deduced from the resonance spect
rum of the input electrical impedance of the composite resonator consisted
of a thin film deposited on a substrate, the density rho, stiffed elastic c
onstant C-33(,)D electromechanical coupling constant k(l)(2) of the film an
d the elastic constant C-33 of the substrate can be calculated directly. Th
en the dielectric constant epsilon (s)(33) can be calculated from the value
s of the parameters above and the input impedance at some special resonance
frequencies. When epsilon (S)(33), C-33(D) and k(l)(2) are known, piezoele
ctric constant h(33) can be obtained. The accuracy of the method is checked
on two typical samples by numerical simulation.