Piezoelectric discharge characteristic of semiconductor ZnO nanorod was studied with atomic force microscope in contact mode. The c-axial orientation ZnO nanorod array film was fabricated with two-step wet-chemical method. Electric pulses were got when Pt coated probe contact-scans the ZnO nanorod, their peak value reaches 120 pA. The electric pulse is related with the topography of ZnO nanorod and has a time duration of 30 ms. The contact of Pt coated probe and ZnO nanorod behaves as a Schottky diode. The I-V curve showed the piezoelectric voltage must be larger than 03 V to drive Schottky diode. The resistance of Schottky contact has a magnitude of GΩ order during piezoelectric discharge, which is the major factor impacting the output of piezoelectric potential.