The invention discloses an optical structure and method for shortening the RGB light mixing distance. The optical structure comprises a PCB; a plurality of RGB light sources which are arranged on oneside of the PCB at intervals; a
light guide plate which is arranged on one side of the PCB; a
light guide plate which includes a plurality of light sources which are distributed at intervals and correspond to the plurality of RGB light sources respectively, wherein each
light guide strip is in a long strip shape, the end face, opposite to the RGB
light source, of each light guide strip forms a light inlet face, the side face of each light guide strip forms a side reflection face, and light emitted by each RGB
light source passes through the corresponding light inlet face and then is reflectedby the side reflection face multiple times to reduce the reflection angle of the light; and a light mixing part, wherein one end of the light mixing part is connected with the other ends of the plurality of light guide strips, and the light mixed by the plurality of light guide strips enters the light mixing part for secondary light mixing. According to the optical structure capable of shorteningthe RGB light mixing distance, light entering the light incoming surface is reflected multiple times through the light guide plate and then mixed, the RGB light mixing distance can be shortened, and the optical structure has the advantages of being simple in structure, convenient to use and the like.