[en] Highlights: • The 3D flower-like ZnO assembled by 1D nanorods was successfully synthesized. • Such flower-like ZnO realizes an enhanced ethanol sensing properties under UV illumination. • The strategy for the joint role may provide a way to further enhance the gas sensing properties. Nanorod-assembled flower-like ZnO was successfully synthesized using a simple hydrothermal method. The measurement results demonstrated that the ethanol sensing properties of the as-prepared ZnO nanostructure were improved once under UV illumination, with higher response and faster response-recovery speed as compared to that in dark condition. The sensing enhancement could be ascribed to the co-effect of the 3D ZnO nanostructure and UV irradiation. Specifically, the 3D framework constructed from 1D nanorods provided plenty of reaction sites and effective gas diffusion pathways. In addition, owing to photo-induced electron-hole pairs under UV irradiation, more energetically free carriers interacted with gas molecules, which accounted for the improvement in ethanol sensing behaviours.