A front cover assembly includes a frame, a cover glass, and a waterproof glue. The frame has a receiving cavity. The cover glass is partially received in the frame. The cover glass has a light exiting face and a lateral face extending from the light exiting face. The cover glass has a step portion located at the lateral face and extending toward the frame. A gap is defined between the step portion of the cover glass and the frame. A waterproof glue fills the gap and directly contacts the step portion and the frame. This assembly can prevent water or dust from entering a terminal device.