The invention discloses a deep-ultraviolet photoelectric detector of an amorphous gallium oxide-based thin film transistor. The deep-ultraviolet photoelectric detector comprises the thin film transistor, wherein the transistor comprises a substrate, a gate electrode, a gate dielectric layer, a channel layer, a source electrode and a drain electrode, the channel layer is an amorphous gallium oxide-based thin film, the thin film transistor is of a bottom gate structure, the gate electrode is arranged on the substrate, the gate dielectric layer covers the gate electrode, the channel covers an upper part of the gate dielectric layer, the source and the drain are respectively arranged at two ends of the channel layer, or the thin film transistor is of a top gate structure, the channel layer covers the substrate, the gate dielectric layer covers an upper part of the channel layer, the source electrode and the drain electrode are respectively arranged at two ends of the gate dielectric layer,and the gate electrode is arranged on the gate dielectric layer. The deep-ultraviolet photoelectric detector provided by the invention has the advantages of relatively high response and low power consumption under irradiation of deep ultraviolet light (320 nanometers), and moreover, the fabrication method is simple, large-area integration can be achieved, and the deep-ultraviolet photoelectric detector is compatible with a flexible substrate.