A light emitting system is disclosed, including a light generator, a complex lens and an activating unit. The light generator provides a light beam emitted in a first direction in parallel to an optic axis. The complex lens, disposed on a path of the light beam, includes a plurality of micro structures for refracting the light beam. The activating unit includes an activating member coupled to the complex lens. The activating member activates the complex lens with an activation frequency to reciprocally move in a second direction alternate to the first direction. By the disposition of the complex lens, the energy of the light beam is uniformly distributed. Additionally, speckle produced by the light beam is reciprocally moved within an area by the activating unit, creating a photogene reaction, to successfully eliminate existence of the speckle.