An optical sensor package structure includes a substrate, a metal plate, an optical sensing chip, a plurality of bonding wires and a lens module. The substrate includes a top surface, a bottom surface and a hole penetrating the top surface and the bottom surface. The metal plate covers the hole from the bottom surface of the substrate. The optical sensing chip is received in the hole and mounted on the metal plate. The bonding wires interconnect the optical sensing chip and the top surface of substrate. The lens module is covering on the hole and mounting on the top surface of the substrate to enclose the optical sensing chip and the bonding wires. Because the optical sensing chip is received in the hole of the substrate, the height of the optical sensor package structure can be reduced to adapt to a compact size electrical device.