The electrical service behavior of ZnO nanowires (NWs) with various diameters was investigated by a nanomanipulation technique. The nanodamage and nanofailure phenomena of the ZnO NWs were observed when external voltages were applied. The threshold voltages of the ZnO NWs increased linearly from 15 to 60 V with increasing diameter. The critical current densities were distributed from 19.50 × 10(6) to 56.90 × 10(6) A m(-2), and the reciprocal of the critical current density increased linearly with increasing diameter as well. The thermal core-shell model was proposed to explain the nanodamage and nanofailure mechanism of ZnO NWs under an electric field. It can be expected that the investigation on the nanodamage and nanofailure of nanomaterials would have a profound influence on practical applications of photoelectric, electromechanical, and piezoelectric nanodevices.