Honeycomb-like NiO/ZnO heterostructured nanorods (NRs) were fabricated by a simple photochemical deposition method. The morphology of the NiO nanostructures can be rationally tailored by changing the concentration of the solution, reaction time and annealing temperature. A reasonable formation mechanism of the honeycomb-like NiO/ZnO NRs is proposed, which is closely related to the production of OH⁻ in the vicinity of ZnO NRs during the photochemical deposition process. The fabricated NiO/ZnO p–n heterojunction shows a well-defined rectifying characteristic with a turn-on voltage of 0.66 V and a negligible leakage current. Moreover, the UV detection performance increases considerably compared to that of bare ZnO NRs, which is attributed to the change of nanostructure and the extended carrier depletion region near p-NiO/n-ZnO junctions.