A high-voltage Schottky diode and a manufacturing method thereof are disclosed in the present disclosure. The diode includes: a P-type substrate and two N-type buried layers, a first N-type buried layer is located below a cathode lead-out area, and a second N-type buried layer is located below a cathode region; an epitaxial layer; two N-type well regions located on the epitaxial layer, a first N-type well region is a lateral drift region and it is provided with a cathode lead-out region, and a second N-type well region is located on the second N-type buried layer and it is a cathode region; a first P-type well region located on the second N-type buried layer and surrounding the cathode region; a field oxide isolation region located on the lateral drift region; an anode located on the cathode region and a cathode located on the surface of the cathode lead-out region.