The invention discloses a novel GaN junction barrier Schottky diode and a preparation method thereof, which provides a new way for improving the performance of the Schottky diode by utilizing a noveldesign and a relatively simple and easily-achieved process. The novel GaN junction barrier Schottky diode sequentially comprises a cathode, a substrate, an n+ type GaN epitaxial layer, an n type GaN epitaxial layer, a high-resistance region, a comb-shaped p type GaN epitaxial layer, a comb-shaped p+ type GaN epitaxial layer and an anode from bottom to top, wherein plasmas are annularly injected into the outer edge of the n type GaN epitaxial layer to form the high-resistance region. According to the invention, p-type GaN does not need to be grown in the n-type GaN layer and a subsequent activation process is not needed, so that the process difficulty and the complexity are greatly reduced. Through the four layers of epitaxial GaN structures, good ohmic contact and better PN junctions can be formed, the forward on resistance is reduced, the reverse breakdown voltage is increased, and the performance of the device is effectively improved. In addition, the high-resistance region formed byN2 Plasma can effectively inhibit breakdown of the device at the edge of an electrode under high voltage, and the breakdown performance is enhanced.