In the pickling process of carbon steel, it is often necessary to add an appropriate amount of pickling corrosion inhibitors to prevent the steel surface from over-pickling and to eliminate the potential for hydrogen embrittlement during the process. Carbon dots (CDs), as a kind of green nano-material, are environmentally-friendly, low-cost, chemically stable and have potentially high inhibition performance, gradually showing good prospects for application in the field of corrosion protection. In this paper, the research progress of carbon dots in the field of metal corrosion protection of carbon steel in acidic media both domestically and internationally in recent years was reviewed, and their inhibition mechanism was discussed; the problems existing in the research of corrosion and protection were briefly described, and the development trend of CDs in the field of metal corrosion and protection was also prospected.