A power module includes a printed circuit board, a magnetic element, a secondary side switching circuit and at least two groups of external terminals. The magnetic element is disposed on the printed circuit board. The magnetic element includes at least one primary winding and plural secondary windings. The secondary side switching circuit includes a plurality of secondary switching units. Each secondary switching unit includes a plurality of switches connected in parallel. The switches of each secondary switching unit are evenly distributed on a first surface and a second surface of the printed circuit board. The switches of the secondary switching unit on the first surface and the second surface of the printed circuit board are at least partially overlapped with each other. The at least two groups of external terminals are disposed on the second surface of the printed circuit board, and electrically connected with the secondary side switching circuit.