Various embodiments may relate to a lens for an illumination device, including an incident surface, an emergent surface, and a reflective surface connected between the incident surface and the emergent surface. The lens includes a first axis as an optical axis of the lens, a second axis perpendicular to the first axis and extending in a longitudinal direction of the lens, the first axis and the second axis defining a symmetrical surface of the lens, and a third axis perpendicular to the symmetrical surface, a first portion of light from a light source is incident upon the incident surface, refracted by the emergent surface, and then emerges to form a first light beam, and a second portion of light from the light source is incident upon the incident surface, reflected by the reflective surface, refracted by the emergent surface, and then emerges to form a second light beam.