An image sensor and a manufacturing method thereof are provided. The image sensor includes a substrate, a patterned electrode layer, a pixel isolation structure and a patterned photo-electric conversion layer. The patterned electrode layer is disposed on the substrate and includes a plurality of electrode blocks separated from one another. The pixel isolation structure is disposed on the substrate and includes a metal halide. The patterned photo-electric conversion layer is disposed on the electrode blocks to form a plurality of photo-electric conversion blocks corresponding to the electrode blocks. The photo-electric conversion blocks include a perovskite material. The photo-electric conversion blocks are separated from one another by the pixel isolation structure.