The invention discloses a high-threshold power semiconductor device and a manufacturing method thereof. The high-threshold power semiconductor device sequentially comprises a drain metal electrode, asubstrate, a buffer layer and a drift region from bottom to top, and also comprises: a composite column body on the drift region, formed by a drift region protrusion, a columnar p region and a columnar n region, and a channel layer, a passivation layer, a dielectric layer, a heavily doped semiconductor layer, a gate metal electrode and a source metal electrode. The composite column body is formedby sequentially depositing a p-type semiconductor layer and an n-type semiconductor layer on the drift region and then etching the p-type semiconductor layer and the n-type semiconductor layer; wherein the channel layer and the passivation layer are formed by deposition in sequence. Therefore, the device is divided into a cellular region and a terminal region. The dielectric layer, the heavily doped semiconductor layer, the gate metal electrode and the source metal electrode only exist in the cellular region, and the passivation layer of the terminal region extends upwards and wraps the outerside of the channel layer. The structure can improve the threshold voltage of the device, improve the blocking characteristic of the device, and reduce the gate capacitance.