A process of manufacturing a package base of a power semiconductor device includes the following steps. Firstly, a semiconductor substrate including a first surface and a second surface is provided. Then, a portion of the semiconductor substrate is patterned and removed to form a recess on the first surface of the semiconductor substrate, which serves as a receiving space for receiving a power semiconductor element therein. Then, a conducting layer is overlaid on the first surface including the receiving space. Afterward, a portion of the conducting layer is patterned and removed to form a conducting structure to be electrically connected to the power semiconductor device.