An illumination system that includes a light source device and an algorithm unit is provided. The algorithm unit is coupled to the light source device and outputs a control signal to the light source device according to a reflection spectrum of an object, a visual color matching function, a visual preference correction function, or a combination of the above. The light source device outputs an illumination beam according to the control signal, so as to develop target visual perception of the object while the object is being irradiated by the illumination beam. A method for developing target visual perception of an object is also provided.