The invention discloses a high-definition digital X-ray flat panel detector which comprises a protective layer, an electrode layer, an insulating layer, an X-ray semiconductor layer, an electronic closing layer, an amorphous selenium layer, a thin film transistor layer, a storage capacitor, a charge amplifier, a gate control circuit, a digital converter and a glass substrate. With the adoption of the mode, the high-definition digital X-ray flat panel detector eliminates image blurring caused by photoelectric scattering, ensures the quality of an image, and can be very reliable in a high-humidity and completely-exposed environment.