A hair darkening dye composition comprises: 2 98 parts by weight of hair dye 1 99 parts by weight of darkening agent 2 98 parts by weight of crosslinking agent 2 98 parts by weight of emulsifier 2 98 parts by weight of dyeing auxiliaries and 0.1 40 parts by weight of pH regulator. The darkening agent is selected from one or more of chitin chitosan gelatin silicon oil and resin. The chitin chitosan and gelatin have relative molecular weight less than 2.7×10 4. Both the silicon oil and the resin have a refractive index less than 1.55.
