This invention presents a solar light collecting and guiding system for stabilizing the output light intensity, wherein the system comprising an array of converging lenses and optical fibers for collecting light focused by converging lenses. The fibers and the lenses are in one-to-one correspondence wherein the input end of an optical fiber is located in the focus position of the corresponding converging lens, and the axis of the optical fiber overlaps with the principal axis of the corresponding converging lens. The system is equipped with a sunlight tracking positioning device for synchronized motion, wherein the device is applied to tracking the sun light ray vertical incident into the central converging lens. The system has the function of outputting stable light intensity, that is, it can effectively reduce the variation of the collecting efficiency caused by the positioning deviation between the incident angle of sunlight and the designed input angle.