Complying with the trend of small size, multi-functionality, and high density integration of photoelectric detectors and arrays, a high-performance solar-blind and X-ray dual function detector basedon ultra-thin Ga₂O₃ was reported. Based on the metal-organic chemical vapor deposition, through fine tuning of growth at high temperature, a thin thickness (70 nm) of high-quality gallium oxide heteroepitaxial thin film is realized. Owing to the ultra-wide band gap of Ga₂O₃ and the high quality of the film, metal-semiconductor-metal structure photodetector based on this film has achieved a photo-to-dark current ratio of 5.5×10⁷, detectivity of 4.65×10¹⁵ Jones, external quantum efficiency of 3.53×10⁴%, and responsivity of 72.23 A/W in solar-blind ultraviolet detection band. What's more, the above-mentioned solar-blind ultraviolet performances remain stable relatively at different solar-blind light intensities (14.7~548 μW/cm²). While for X-ray detection, an ultra-high sensitivity of 1.91×10⁴ μC·cm^-2·Gy^-1 is achieved, which exceeds the previously reported Ga₂O₃ thin-film detectors under the equivalent thickness. Besides, the device can still achieve comprehensively high performance at a lower operating voltage. The improvement of film quality, ionization of intrinsic oxygen vacancies, and photoinduced Schottky barrier reduction effect etc. conribute to the excellent photoresponse performance of this Ga₂O₃ thin-film detectors under both solar-blind and X-ray illumination. Additionally, the cascade effect casused by the X-ray induced high-erergy electrons is another critial aspect for the high X-ray sensitivity of the device. This work provides potential inspirations for ultra-thin solar-blind and X-ray detectors with high performance and low power consumption in the future.