Utilizing silica micropillar arrays as substrate, a kind of Zinc oxide (ZnO) nanowires/Cadmium sulfide (CdS) nanopillars heterojunction structure is prepared successfully by twice hydrothermal reaction method. This ZnO nanowires/CdS nanorods/silica micropillars structure is tree-liked morphology from the SEM and TEM images, and both the ZnO nanowires and CdS nanorods are well crystallinity on the silica surface from the X-ray diffraction curves. The CdS nanorods/silica micropillars structure has a low reflectivity to the incoming light for wavelength from 200 to 800 nm. After the ZnO nanowires growing, the reflectivity of tree-liked structure is much lower than that without ZnO nanowires especially for the wavelength less than 350 nm. The resistance response of the CdS nanorods/silica micropillars based photoresistors with and without ZnO nanowires are tested. And the results reveal that the ZnO nanowires covering can improve the response of the CdS nanorods/silica micropillars photoresistors. The best photosensitivity response of the ZnO nanowires/CdS nanorods/silica micropillars photoresistor for 450 nm wavelength light with 5 mW/cm² illumination can achieve to 23.3, while that for CdS nanorods/silica micropillars photoresistors is 18.8.

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