As a new generation of wide bandgap semiconductor, gallium oxide has a larger bandgap width (4.4~4.8 eV) and higher breakdown field strength (8 MV/cm), making it an ideal material for fabricating high voltage, high frequency, and high power electronic devices. However, due to the edge concentration effect of the terminal electric field of gallium oxide Schottky diodes, the device fails due to premature breakdown, thus limiting the application of gallium oxide. A new type of composite terminal is designed in this paper, which is formed by combining a high-resistance region that can alleviate the edge concentration effect of the electric field and an electron barrier layer that suppresses reverse leakage. The simulation results show that the peak electric field near the edge of the device electrode that introduces the high-resistance region terminal structure drops from 3.650 MV/cm to 0.246 MV/cm, which can effectively alleviate the edge concentration effect of the electrode electric field. When the Mg ion implantation concentration in the high-resistance region is 10¹⁹ cm^-3, the breakdown voltage increases from 725 V to 2 115 V, the Baliga figure of merit increases from 0.060 GW/cm² to 0.247 GW/cm², and the critical breakdown field strength increases by 50.7% (from 3.650 MV/cm to 5.500 MV/cm); at the same time, the introduction of the electronic barrier layer AlN greatly reduces the reverse leakage current of the device, and the reverse breakdown voltage increases to 2 690 V, which is beneficial to the new composite terminal. The new composite structure can not only effectively suppress the reverse leakage current of the device but also effectively increase the reverse breakdown voltage of the device. This research lays a theoretical foundation for the development of high voltage resistant, low reverse leakage current gallium oxide Schottky diodes.