The present disclosure provides an assembly method of an electronic device. The assembly method includes: opening an upper cover of a loading mechanism on a circuit board, in which the upper cover has an opening, and when the upper cover is in a closed state, the opening exposes a central processing unit socket located on the circuit board; snapping an elastic sheet to opposite sides of an inner edge of the opening of the upper cover through buckling portion of the elastic sheet; and closing the upper cover of the loading mechanism so that an elastic sheet body of the elastic sheet covers the central processing unit socket.