A CMOS sensor array includes a plurality of unit blocks. A unit block includes: N pairs of photo diode regions arranged in a first direction; 2N transfer transistors respectively corresponding to the photo diode regions, wherein each of the transfer transistors is formed at a corner of the corresponding photo diode region, and wherein for each pair of photo diode regions the two corresponding transfer transistors symmetrically oppose each other; N floating diffusion nodes, wherein each of the floating diffusion nodes is respectively arranged between a pair of photo diode regions, and wherein each of the floating diffusion nodes is shared by the two corresponding transfer transistors and the pair of photo diode regions; at least one metal line for coupling the floating diffusion nodes; a reset transistor for resetting a voltage of the floating diffusion nodes; a readout circuit including at least one transistor for sampling the floating diffusion node, wherein the reset transistor and the readout circuit are disposed between the pair of photo diode regions.