A light and disinfection system for disinfecting an illuminated surface has anilluminationmodule, including an illumination source； a distance sensor for detecting adistance between thelight and disinfection system and the illuminated surface； and a disinfectionmodule, including adisinfection light source and a control unit, the control unit receiving thedistance detected bythe distance sensor and controlling an irradiation power of the disinfectionlight source based onthe distance, such that an irradiation amount of the illuminated surfaceaccumulated within onedisinfection circle is kept at a predetermined value. A method fordisinfecting an illuminatedsurface by the light and disinfection system includes detecting a distancebetween the light anddisinfection system and the illuminated surface； and controlling anirradiation power of adisinfection light source in the light and disinfection system based on thedistance.
