The polycrystal CuO curved nanowires were synthesized on Cu mesh by a facile alkalization method. The visible light-driven CuO curved nanowires were observed to have highly sensitivity for non-enzymatic ethanol sensing in solution and fast antibacterial property under flashlight irradiation. Compared to the single-crystal CuO nanowires, the polycrystal CuO nanowires were investigated based on the analysis of the morphology, nanostructure, theoretical modeling, and photoelectrochemical performance. As a result, the highest photocurrent densities were obtained by polycrystal CuO curved nanowires, as the facet heterojunction in curved nanowires played a key role, which existed in the interface between facets CuO (111) and CuO (110) resulting in the effectively separation of photoelectron-holes, thereby increasing the charge carrier density. Herein, the CuO curved nanowires were assembled as a photoelectrochemical sensor to detect the low concentration ethanol ranging from 10 to 100 nM, and then showed a high sensitivity. The fast antibacterial performance of CuO curved nanowires was found to completely kill 107 CFU/mL E.coli under flashlight irradiation in 20 minutes. The proposed CuO curved nanowires electrode with self-cleaning performance can be ideal for monitoring the low concentration ethanol in real-time at room temperature as photoelectrodes.