The present invention relates to a piezoelectric micro acoustic sensor based on ferroelectric materials. In one embodiment, more than one electrode pairs are provided within at least one of the central portion and the peripheral portion of a ferroelectric film of the sensor, a polarizing voltage is applied to each electrode pair so that regions of the ferroelectric film between each electrode pair is polarized along the thickness direction, and in a same stress state portion of the film regions of the ferroelectric film between neighboring electrode pairs are polarized in opposite directions, hence the neighboring electrode pairs within the same stress state portion have opposite voltages when the ferroelectric film vibrates. In one embodiment, all of the electrode pairs are connected in series, so that the output voltage of thus connected electrode pairs equals to the sum of voltages of each single pair. Therefore the voltage sensitivity of the piezoelectric micro acoustic sensor is improved significantly.