The invention relates to a covering device for an expansion joint of a bridge pavement. The covering device for the expansion joint of the bridge pavement is used for covering a pavement part of the bridge expansion joint, and comprises a rubber body (9) flush with the horizontal height of the bridge pavement, a support body (8) located inside the rubber body (9), and two extending support pieces (7) capable of moving face to face and reversely in the support body (8) and having mutually symmetrical structures, wherein each of the extending support pieces (7) comprises a horizontal extending head part (721) capable of horizontally sliding in a sliding chute (81) of the support body (8), a vertical extending part (72) connected with the horizontal extending head part (721), and a support arm (71) connected with the lower end of the vertical extending part (72) and extending toward an adjacent bridge structure body; support plates (73) abutted with the adjacent bridge structure body are respectively arranged on end parts of the two extending support pieces (7).