Display panel and vehicle tail lamp

The utility model provides a display panel and a vehicle tail lamp. The display panel comprises a substrate, an anode, a pixel defining layer, a light emitting unit, a cathode, an insulating layer and an auxiliary cathode. The anodes are arranged on one side of the substrate and are arranged at intervals. The pixel defining layer is arranged on the side, away from the substrate, of the anode and comprises a body part and opening parts, and the opening parts are in one-to-one correspondence with the anode and expose at least part of the anode. Light-emitting units and cathodes which are in one-to-one correspondence with the anodes are sequentially arranged on the side, away from the substrate, of the pixel defining layer, the light-emitting units are red light-emitting units, insulating layers are arranged between the adjacent light-emitting units, and the orthographic projection of the insulating layers on the substrate is located within the orthographic projection range of the body part on the substrate. And the height of one surface, far away from the substrate, of the insulating layer is between the surfaces, close to and far away from the substrate, of the cathode. The auxiliary cathode is arranged on one side, far away from the substrate, of the insulating layer; and the auxiliary cathode is at least partially lapped with the cathode.