The invention relates to the technical field of semiconductors, and specifically relates to a gate heterojunction device. The gate heterojunction device mainly adopts a second kind semiconductor and a third kind to form a heterojunction, an insulating layer is arranged on an ohmic contact S end, a gate grid is arranged between a source electrode and a drain electrode, and the on-off state of a grid channel is controlled by the structure of the gate grid; in addition, when no voltage is applied to the device, by controlling the thickness of a third kind semiconductor in the gate grid and the concentration of doped positive and negative ions, the device is enabled to be a normally-closed device, and forward and reverse voltage resistance of the device is realized through the growth length between a grid drain electrode and a source drain electrode. The gate heterojunction device has the advantages that the gate heterojunction device is the normally-closed device, integration and layout are realized in a heterojunction type HEMTs, the technology compatibility is good, the performance is stable under a high-temperature high-field environment, and the voltage resistance of the circuit is controllable.