The invention discloses a stack gate enhanced GaN high-electron-mobility transistor containing a ferroelectric gate dielectric, which mainly solves a problem of poor reliability of the existing similar devices. The stack gate enhanced GaN high-electron-mobility transistor comprises a substrate, an AlN nucleation layer, a GaN buffer layer, an AlN insertion layer, an AlGaN barrier layer, a GaN cap layer, an SiN passivation layer, a gate dielectric layer and an SiN protection layer from the bottom up, wherein the SiN passivation layer is provided with a concave structure, the inner wall of the concave structure and the surface of the SiN passivation layer are provided with the gate dielectric layer, the gate dielectric layer comprises an AlN or Al2O3 dielectric insertion layer and an HfZrO ferroelectric layer, two ends of the GaN buffer layer are provided with a source electrode and a drain electrode respectively, the middle of the gate dielectric layer is provided with a gate electrode, the source electrode and the drain electrode are provided with a metal interconnection layer, and the gate electrode and the gate dielectric layer at the surface of the passivation layer are covered with the SiN protection layer. According to the invention, the reliability of the device is improved, gate leakage of the enhanced device is reduced, and the transistor can be used as a switching device requiring high threshold voltage.