The invention discloses a Ga2O3 Schottky diode device structure and a manufacturing method thereof, and mainly aims at solving the problems that a present Schottky diode device is low in reverse breakdown voltage and the parasitic capacitance in a field plate structure is high. The Ga2O3 Schottky diode device structure comprises a cathode electrode, a heavily-doped n type Ga2O3 substrate, a low-doped n type Ga2O3 epitaxial layer and an anode electrode from bottom to top; Schottky contact is formed in the part where the anode makes contact with the epitaxial layer, the cathode and the substrate make ohmic contact, grooves are distributed separately in the low-doped n type Ga2O3 epitaxial layer, intervals of grooves are increased progressively within the range of 0.3 to 0.5 micron, the first groove is positioned below the edge of the anode, the distance between the last groove and the first groove ranges from 10 to 15 micron, and AlGaO layers in which the Al component is greater than 20% are grown in an epitaxial manner in the grooves respectively. Thus, the reverse breakdown voltage is improved, the parasitic capacitance is reduced, positive characteristic is kept unchanged, and the structure and manufacturing method thereof can be used for high-speed integration circuits and microwave technologies.