PZT nano particles have been prepared by the megahertz ultrasound treatment on the micro PZT powders in anhydrous ethyl alcohol solution. The sample was dropped on the surface of silicon wafer being evaporated with gold and was dried, then the two dimensional size，surface morphology and longitudinal piezoelectric coefficient were observed using PFM. It is demonstrated that the longitudinal piezoelectric coefficients of the micro and nano PZT powders fluctuated in the range of 20 40 pm/V, and 2 10 pm/V respectively, both of the samples had the piezoelectric properties. This method might provide a feasible technical approach for the preparation of piezoelectric thick film.