An illumination module includes a light emitting unit, an optical lens with positive refractive power, and a concave mirror. At least one of an object-side surface and an image-side surface of the optical lens is an asymmetrical surface, and the light emitting unit is provided at an object side of the optical lens. The concave mirror is provided at an image side of the optical lens, and the concave mirror acts as an optical path folding element. Light emitted by the light emitting unit passes through the optical lens and is reflected by the concave mirror to be a parallel light ray.