Abstract: Due to the lack of p-type gallium oxide, the pn junction terminal extension structure (JTE), which is highly effective in modulating the electric field, cannot be used. This article proposes the use of p-GaN and n-Ga2O3 to form a pn junction JTE structure, effectively solving this problem. In order to provide theoretical guidance for further improving the breakdown voltage of gallium oxide Schottky barrier diodes (SBD), in this article, Silvaco software was used to simulate the p-GaN/n-Ga2O3 JTE SBD. Compared with the control SBD , it was found that the breakdown voltage of the p-GaN/n-Ga2O3 JTE SBD increased from 880V to 1349V, at the cost of slightly increasing the forward conduction resistance of the device. The influence of p-GaN depth on the characteristics of SBD is investigated. It is found that the p-GaN depth is from 0.3μm increased to 1.2μm, the breakdown voltage of the device is further increased from 1349V to 1685V, and the Ron of the device is basically unchanged. This paper proves the feasibility of p-GaN/n-Ga2O3 JTE structure to improve the reverse breakdown characteristics of SBD through simulation experiments.