ZnO-CeO2 nanostructures were synthesized by simple and effcient low temperature method. The structure and morphology of the ZnO-CeO2 nanostructures were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM), which revealed elongated shaped CeO2 nanoparticles with diameters of 40-90 nm distributed on the surface of elongated ZnO nanostructures with diameters of 50-200 nm (edge-centre). Further the structure of the synthesized ZnO-CeO2 nanostructure was supported by Raman spectra and Fourier transform infrared spectroscopy (FTIR). UV-vis absorption spectrum was used to confirm the optical properties of the CeO2 doped ZnO nanostructures. Photo-catalytic activity of CeO2 doped ZnO nanostructure was evaluated by degradation of acridine orange and methylene blue which degraded 84.55% and 48.65% in 170 min, respectively. ZnO-CeO2 nanostructures also showed good sensitivity (0.8331 μA·cm-2·(mol/l)-1) in short response time (10 s) by applying to chemical sensing using ethanol as a target compound by I-V technique. These degradation and chemical sensing properties of ZnO-CeO2 nanostructures are of great importance for the application of ZnO-CeO2 system as a photo-catalyst and chemical sensor. ZnO-CeO2 nanostructures were synthesized by simple and effcient low temperature method. The structure and morphology of the ZnO-CeO2 nanostructures were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM), which revealed elongated shaped CeO2 nanoparticles with diameters of 40-90 nm distributed on the surface of elongated ZnO nanostructures with diameters of 50-200 nm (edge-center). Further the structure of the synthesized ZnO-CeO2 nanostructure was supported by Raman spectra and Fourier transform infrared spectroscopy ( FTIR). UV-vis absorption spectrum was used to confirm the optical properties of the CeO2 doped ZnO nanostructures. Photo-catalytic activity of CeO2 doped ZnO nanostructure was evaluated by degradation of acridine orange and methylene blue which degraded 84.55% and 48.65% in 170 min, respectively. ZnO-CeO2 nanostructures also showed good sensitivity (0.8331 μA · cm-2 · (mol / l) -1) in short response time (10 s) by applying To chemical sensing using ethanol as a target compound by I-V technique. These degradation and chemical sensing properties of ZnO-CeO2 nanostructures are of great importance for the application of ZnO-CeO2 system as a photo-catalyst and chemical sensor.