Although there are many studies for the characterization of piezoelectric thin film, it is still strongly needed to develop the easy and practical way to measure the piezoelectricity existing in thin film. Piezoelectric properties of lead zirconate titanate (PZT) thin film were investigated by a new pneumatic loading method, which has been devised as a more reliable and convenient characterization technique. We have observed the aging phenomena and have examined the effects of poling voltage and time on piezoelectric properties of the PZT thin films. There was no built-in piezoelectricity in virgin films.