A cover assembly includes a cover including a first cover with a receiving space on the upper surface thereof, a main body having an installing post and connecting the bottom of the first cover, a second cover on the top of the first cover, and a securing portion including a cooperating piece, a flexible section and a latching rim extending from the flexible section in a direction perpendicular to the flexible section; wherein the second cover has a latch cavity to form a passage with an open defined in the first cover and penetrating along up-to-down direction, the cooperating piece is rotatably assembled with the installing post and the securing portion is capable of rotating around the installing post to achieve a fixed position and an engaging position on which the cooperating piece is inserted in the passage to assemble the two covers and the main body together.