A hall sensor possessing a two-dimensional electron gas channel barrier layer local groove structure and a manufacturing method belong to the semiconductor sensor field. A buffer layer, an epitaxial layer and a barrier layer successively grow on a semiconductor substrate. The surface of the barrier layer is provided with three main electrodes C0, C1 and C2. The main electrodes C1 and C2 are centrally symmetrical about the main electrode C0. Groove structures are arranged between the main electrodes C0 and C1 and between the main electrodes C0 and C2. Two side groove structures are centrally symmetrical about the main electrode C0. The width of each groove structure is less than an electrode distance between the C0 and the C1 or the C0 and the C2. The groove structure between the main electrodes C0 and C1 is provided with a sensing electrode S1. The groove structure between the main electrodes C0 and C2 is provided with a sensing electrode S2. In the invention, through the shallow etching of a selection area, a groove is formed, and an intact heterojunction interface below the groove is kept; and the high mobility advantage of a two-dimensional electron gas can be used and a movingcarrier under a weak magnetic field signal can be ensured to generate effective offset so that device detection sensitivity is increased.