A power adapter and a manufacturing method thereof are provided. The power adapter includes a housing, a circuit board assembly, and a first heat dissipation part. There is accommodation space inside the housing, a line interface is disposed at a first end of the housing, and a power connector is disposed at a second end of the housing. The circuit board assembly is disposed in the accommodation space, and the circuit board assembly is electrically connected to the line interface and the power connector. The first heat dissipation part coats the outside of the circuit board assembly, and there is a gap between an outer wall of the first heat dissipation part and an inner wall of the housing.