Abstract: A power adapter comprises a cover and a printed circuit board module received in the cover. The cover has a base and an upper cover covering the base, the base has a bottom wall and a plurality of side walls surrounding the bottom wall, the bottom wall and the side walls form a receiving space for receiving the printed circuit board module. The cover has a plurality of latching members at the top of the side wall, the latching members are on both ends of the cover, the latching members are defined above the upper cover and extend to each other. The side walls comprise a first side wall with a rotatablely movable block, the latching member is defined at the top of the movable block, the latching member moves outward with the movable block rotating.