Abstract: A connecting structure includes a coating component provided with a storage cavity and a first through hole, an expansion component provided with a second through hole and a first fastener. A part of the expansion component is stored in the storage cavity. The expansion component has a rotary state and a fixed state relative to the coating component. When the expansion component is in the rotary state, the expansion component can be rotated relative to the coating component. The first fastener can pass through the first through hole and extend into the second through hole to make the expansion component expand. The outer surface of the expansion component is pressed against the inner surface of the coating component to fix the expansion component in the coating component. The expansion component is in the fixed state relative to the coating component.