The invention relates to the technical field of illumination, in particular to a bottom-incidence reflecting cover and a vehicle lamp with the bottom-incidence reflecting cover. The reflecting cover comprises a cover body. The cover body is provided with a reflecting cavity. The reflecting cavity is provided with a gap through which a light source is installed or light enters the reflecting cavity. The inner wall of the reflecting cavity comprises a reflecting face used for reflecting light. The reflecting cavity is further provided with an opening through which internal light exits. The opening of the reflecting cavity is provided with a step-shaped edge. The step-shaped edge is matched with the light-shade cut-off shape of a low beam lamp, the gap is opposite to the reflecting face, and light emitted by the light source irradiates the reflecting face at first and then is reflected by the reflecting face to exit from the opening of the reflecting cavity. According to the reflecting cover, the lamp vehicle structure is simplified at first, the manufacturing cost is reduced, the using reliability is improved, shielding of a light shielding plate for light is avoided, and the utilization rate of light emitted by the light source is improved; and meanwhile, the reflecting cover can control light conveniently, and thus the illumination quality of the vehicle lamp is improved.