An array substrate of an X-ray sensor and a method for manufacturing the same are provided, the method comprising a step of forming a thin-film transistor element and a photodiode sensor element, wherein the step of forming the thin-film transistor element comprises: forming a gate electrode on an base substrate by a mask process; depositing a gate insulating layer on the base substrate on which the gate electrode is formed; the step of forming the photodiode sensor element comprises: forming an ohmic contact layer on the base substrate through the same mask process while forming the gate electrode; forming a semiconductor layer and a transparent electrode through a mask process on the substrate on which the ohmic contact layer is formed; depositing the gate insulating layer on the base substrate on which the semiconductor layer and the transparent electrode are formed while depositing the gate insulating layer on the base substrate on which the gate electrode is formed. A gate pattern and an ohmic contact layer are formed through the same mask process, and a passivation layer substitutes a channel blocking layer to reduce the number of the mask processes and simplify the manufacturing process and improve throughput and yield of the product.