The invention provides an X-ray detector and a display device having the X-ray detector. The X-ray detector comprises the following parts of a scintillator located on the light incident side of the X-ray detector and converting an X-ray into visible light; a thin film transistor; a photosensitive layer disposed between the scintillator and the thin film transistor and comprising a transparent conductive thin film and a mesoporous silicon layer, wherein the mesoporous silicon layer is electrically connected to the drain of the thin film transistor, the transparent conductive thin film is disposed on the light incident side of the mesoporous silicon layer that is in a uniform porous structure, and silicon particles are filled in the porous; and a light shielding member located between the scintillator and the thin film transistor and corresponding to the position of the active layer of the thin film transistor to shield the incident light of the active layer. The X-ray detector providedby the invention using mesoporous silicon as a photoelectric conversion layer is more sensitive to X-ray conversion and has higher photoelectric conversion efficiency.