The opal photonic crystals (PCs) were assembled by vertical deposition of polystyrene microspheres (PS), in which Yb³⁺, Er³⁺ co-doped ZnO powders were deposited on the surface of PC films. The phase, structure and morphology of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The performance of up-conversion photoluminescence (UCPL) was investigated by fluorescence spectrophotometer. The up-conversion (UC) emission of ZnO:Yb³⁺/Er³⁺ on the PC surface is notably enhanced when the UC emission wavelength is overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. The results show that PCs may have potential applications in the enhancement of UCPL and optoelectronic devices.