A novel high voltage and low power Schottky barrier diode (SBD) with double-heterojunction was theoretically and experimentally investigated on the GaN/AlGaN/GaN/Si substrate. Owing to the polarization effect, the two-dimensional hole gas (2DHG) and electron gas (2DEG) were formed at the GaN-top/AlGaN and AlGaN/GaN interface, respectively. Firstly, with the increase of bias voltage, the 2DHG and 2DEG gas were completely exhausted, leaving a fixed positive/negative polarization charge at the interface to form a polarization junction. The power lines shifted from positive charge to negative charge, which made the distribution of the electric field in the drift area more uniform, and improved the breakdown voltage of the diode. Secondly, the GaN/AlGaN layer of the Schottky diode was completely etched to obtain a low turn-on voltage. Finally, a low damage ICP etching process was developed to reduce the defects of the Schottky contact interface, and to reduce the reverse leakage current and turn-on voltage. The experimental results showed that the breakdown voltage of the diode was 1 109 V@1 mA/mm, the turn-on voltage was 0.68 V, the specific on-resistance was 1.17 mΩ·cm2, and the Baliga FOM value was 1 051 MW/cm2. The SBD had the characteristics of high breakdown voltage, low turn-on voltage and good uniformity