A transverse piezoelectric field-effect transistor (TP-FET) based on single ZnO nanobelts has been fabricated on a metallic graphite substrate in an atomic force microscope (AFM). The source-to-drain current of the TP-FET was found to decrease with increasing loading force under a positive bias due to the carrier-trapping effect and the creation of a charge-depletion zone. This TP-FET can be applied as a force/pressure sensor for measuring nanoNewton forces ranged from 0 to 700 nN.