Zinc oxide has the advantages of a wide bandgap, rich resources, simple preparation, and environmental friendliness. It is a type of ultraviolet detector material with great potential for development. However, the complicated preparation processes and complex device structures limit the application of zinc oxide ultraviolet (UV) detectors. Therefore, in this study, a high-performance UV detector was successfully fabricated based on graphene quantum dot-sensitized GaP@ZnO nanocomposite thin films deposited using a simple spin-coating method.The GQDs/GaP@ZnO device exhibits higher responsibility of 142.2A/W, excellent detectivity of 1.1ⅹ1012 Jones, and a higher EQE of 4.85ⅹ104% under the conditions of 365nm UV light (0.078mW /cm2) and external voltage of 6V. In addition, this study provides a new research method for the preparation of high-performance optoelectronic devices using the cumulative synergistic effect of material composites and surface modification.