The invention provides an optical
system and a lamp. The optical
system comprises a lens and a reflection cup, the lens comprises a lens body, the two opposite sides of the lens body are provided with an installation face and a light emitting face respectively, the installation face sinks towards the lens body to form an installation groove used for arranging a
light source, the top face of the installation groove is a reflection face, and the side wall of the installation groove is a light incident face. A first
optical surface connected with the mounting surface and the light emitting surface is formed on the
peripheral surface of the lens body, the reflection cup is arranged on the outer side of the lens in a sleeving mode, and light rays emitted by a
light source and close to the center portion pass through the lens body twice to form a
rainbow aperture. And the other part of light emitted by the
light source is emitted from the light emitting surface to form a small-angle
light beam. According to the optical
system, on the basis that the lighting effect of the lamp is guaranteed, the effect of generating a
rainbow aperture around an original
light spot is achieved by additionally arranging the reflection cup, and the decoration function is added to the lamp. Therefore, the ornamental value of the light spots is improved, and the selling points of the lamp are increased.