The invention relates to a bridge expansion device and expansion joint components thereof. The bridge expansion device comprises the two expansion joint components installed in a butt-joint mode, and a gap is formed between the two expansion joint components. According to the bridge expansion device and the expansion joint components thereof, the characteristics that concrete is low in breaking strength and high in compressive strength and generates volume shrinkage in the solidification process, and steel bars are poor in bonding force are fully taken into account, and the expansion device and the concrete are integrated into a whole through the bonding strength of the concrete; when an expansion beam is rolled by wheels, force is directly transmitted to a bearing vertical rod arranged under a vertical back body through the vertical back body, the bearing vertical rod further diffuses the force, no bending moment is generated in the whole force transmitting process, and breaking destroy of the bending moment to the concrete in the existing mode that vertical loads of a cross beam cantilever are transmitted through back annular reinforcements is avoided; the condition that in the prior art, micro-gaps in the concrete and the bottom face of a cross beam are caused by the shrinkage characteristic of the concrete is avoided, shock of the cross beam or a connecting plate to the concrete on the lower portion of the cross beam or connecting plate is avoided, then concrete breaking is avoided, the service life of the concrete is prolonged, and the practicability is high.