The utility model relates to an automatic dreg feeding system of a boiler. The system comprises a stand, and is characterized in that a double-auger dreg feeding part is arranged at one end of the stand; the double-auger dreg feeding part comprises a hopper; an opening is formed in the bottom of the hopper; an auger I and an auger II which are parallel to each other are arranged under the hopper; the ends of the auger I and the auger II are respectively connected with output shafts of two auger motors; the other ends of the auger I and the auger II extend to the upper part of a belt-type feeding part. Aiming at solving the problems that the dregs of a decoction are different in length, irregular in shape and difficult to feed, the automatic dreg feeding system adopts the double augers for feeding, so that the feeding uniformity is fully guaranteed; furthermore, the augers can be rotated positively and negatively, so that the phenomenon of blockage caused by large dreg materials or no dreg material can be avoided; the automatic dreg feeding system is good in feeding stability, is capable of conveying the dreg of a decoction without needing manpower, and has the advantages of being good in feeding effect and low in labor intensity of workers.