A method for fabricating a sensor, comprising: forming a pattern of a bias line on a base substrate by using a first patterning process; forming a pattern of a transparent electrode, a pattern of a photodiode, a pattern of a receive electrode, a pattern of a source electrode, a pattern of a drain electrode, a pattern of a data line and a pattern of an ohmic layer by using a second patterning process; forming a pattern of an active layer, a pattern of a first passivation layer, a pattern of a gate electrode and a pattern of a gate line by using a third patterning process. The above method reduces the number of used mask in the fabrication processes as well as the production cost and simplifies the production process, thereby significantly improves the production capacity and the yield rate.