An image sensor having an improved transparent layer includes a substrate, a frame layer, a photosensitive chip, a plurality of wires, and a transparent layer. The substrate has an upper surface formed with a plurality of first connected points. The frame layer is arranged on the upper surface of the substrate so as to form a cavity together with the substrate. The photosensitive chip is mounted on the upper surface of the substrate and within the cavity. The plurality of wires are electrically connected the photosensitive chip to the first connected point of the substrate. The transparent layer is covered on the frame layer for covering the photosensitive chip so that the photosensitive chip may receive optical signals passing through the transparent layer, respectively, at the peripheries of the transparent layer are formed with cut—corners. Therefore, the transparent layer may be decreased collision and may be increased the cleanness of the transparent layer, therefore, simplifying the manufacturing processes and decreasing the manufacturing cost.