The present invention relates to a mordant for hair dyeing and a hair dyeing product comprising the mordant. The mordant of the present invention comprises an effective amount of a ferrous salt antioxidant and water the hair dyeing product of the present invention comprises three parts: a softening agent a dyeing agent and the mordant. The mordant and the hair dyeing product comprising the mordant as provided by the present invention do not contain thioglycolic acid aromatic compounds such as p- phenylenediamine and hydrogen peroxide and are safe and free of irritation . The hair dyeing product of the present invention has good chromaticity and fastness as well as good product stability and convenience in usage.
