A transistor structure including a gate, an insulation layer, a patterned semiconductor layer, a source, a drain and a light absorption layer and a manufacturing method thereof are provided. The gate is disposed on a substrate. An area of the gate overlaps an area of the patterned semiconductor layer. The insulation layer is disposed between the gate and the patterned semiconductor layer. The source and the drain are separated from each other and in contact with the patterned semiconductor layer. The patterned semiconductor layer is disposed between the light absorption layer and the substrate. An area of the light absorption layer overlaps an area of the patterned semiconductor layer. An absorption spectrum of the light absorption layer overlaps an absorption spectrum of the patterned semiconductor layer.