A power device, comprising package body and a plurality of pins, wherein the package body comprises a substrate structure, a semiconductor die, and a molded package, the semiconductor die is disposed on the substrate structure, the substrate structure comprises a heat dissipation surface configured to be connected to a heat sink, a first end of each of the pins is fixed to the substrate structure, the molded package covers the semiconductor die and the substrate structure except the heat dissipation surface, a second end of each of the pins and the heat dissipation surface are both exposed from the molded package, and the second end comprises a mounting surface configured to be mounted to a circuit board; and the power device is further provided with a through hole extending through the substrate structure and the molded package, and an inner wall of the through hole is covered with the molded package, wherein the heat dissipation surface includes at least two heat dissipation surface units, and a gap between adjacent heat dissipation surface units is filled with the molded package; and wherein the package body comprises a top portion, a bottom portion and side portions, the top portion and the bottom portion are disposed opposite each other, the heat dissipation surface is located on the surface of the top portion away from the bottom portion or is located on the surface of the bottom portion away from the top portion, the side portions are connected between the bottom portion and the top portion, an orientation of the bottom portion is the same as that of the mounting surface, and the plurality of pins are distributed along the side portions. the package body comprises a substrate structure, a semiconductor die, and a molded package, the semiconductor die is disposed on the substrate structure, the substrate structure comprises a heat dissipation surface configured to be connected to a heat sink, a first end of each of the pins is fixed to the substrate structure, the molded package covers the semiconductor die and the substrate structure except the heat dissipation surface, a second end of each of the pins and the heat dissipation surface are both exposed from the molded package, and the second end comprises a mounting surface configured to be mounted to a circuit board; and the power device is further provided with a through hole extending through the substrate structure and the molded package, and an inner wall of the through hole is covered with the molded package, wherein the heat dissipation surface includes at least two heat dissipation surface units, and a gap between adjacent heat dissipation surface units is filled with the molded package; and wherein the package body comprises a top portion, a bottom portion and side portions, the top portion and the bottom portion are disposed opposite each other, the heat dissipation surface is located on the surface of the top portion away from the bottom portion or is located on the surface of the bottom portion away from the top portion, the side portions are connected between the bottom portion and the top portion, an orientation of the bottom portion is the same as that of the mounting surface, and the plurality of pins are distributed along the side portions.