The invention discloses an HEMT device and a manufacturing method of the HEMT device. The HEMT device comprises a substrate, an active region formed on the substrate, a barrier region formed on the active region, a blocking region formed on the barrier region, a grid formed on the blocking region, low-resistance regions formed on the two sides of the grid respectively, a source and a drain, wherein the grid is used in the low-resistance regions as masking, the low-resistance regions are formed according to a self-alignment process and are provided with doping particles, and the source and the drain are formed on the low-resistance regions on the two sides of the grid respectively. By means of the HEMT device and the manufacturing method, the grid-source distance and the grid-drain distance are effectively reduced, the grid-source series resistance and the grid-drain series resistance are reduced, and the high frequency characteristic of the device is improved. In addition, accurate alignment is not needed when the low-resistance regions are formed, the requirement for the alignment accuracy of the photolithography technique is reduced, the yield of the device is improved, and the production cost is reduced.