The present invention provides a reverse-phase modulating structure of a piezoelectric ceramic speaker, comprising a positioning frame, an acoustic generator and two or more than two flexible units; wherein the acoustic generator comprises a plurality of ceramic layers stacked onto one another to form a ceramic slat, and said flexible units are clamped between an inner edge of the positioning frame and the acoustic generator. Via the pressure exerted onto the acoustic member by the flexible units, the in-phase movement of the acoustic generator can be modulated and the phase conflict of the acoustic generator can be reduced as well as the prevision of the sound quality distortions such that high quality of the ceramic speaker can be enhanced and realized.