Due to the complexity of electro-elastic coupling characteristics in piezoelectric material, some of the elastic, dielectric and piezoelectric parameters are difficult to be measured. Usually, these parameters are determined by assuming that all offer parameters are remained constant during the measurement. However, the interactive effect between material properties makes this assumption be not always true. In this study, the measured natural frequencies of the specified circular piezoelectric plate are used to extract these parameters simultaneously. In other words, all these parameters are determined with considering the interactive electro-elastic coupling effect. The analytic model of free-free circular piezoceramic plate was derived and solved to establish the relationship between natural frequencies and its material parameters, to cover most all the parameters, the out-of-plane(non-symmetric transverse) and in-plane(symmetric extensional) modes are considered. The genetic algorithm is employed to determine most all elastic, dielectric and piezoelectric parameters from a least square error between the calculated and measured natural frequencies. Numerical results derived from the parameters proposed in this work reveal a good agreement with the measured data. In other words, the proposed method to extract the piezoelectric parameters is feasible and effective.