A MOS P-N junction Schottky diode device includes a substrate having a first conductivity type, a field oxide structure defining a trench structure, a gate structure formed in the trench structure and a doped region having a second conductivity type adjacent to the gate structure in the substrate. An ohmic contact and a Schottky contact are formed at different sides of the gate structure. The method for manufacturing such diode device includes several ion-implanting steps to form several doped sub-regions with different implantation depths to constitute the doped regions. The formed MOS P-N junction Schottky diode device has low forward voltage drop, low reverse leakage current, fast reverse recovery time and high reverse voltage tolerance.