The invention relates to a red liquid dye composition and a preparation method thereof. The dye composition comprises a component A such as acid red 138 (CI.18073), a component B such as acid red 1 (CI.18050), and a component C such as a mixed solution of ethyl alcohol and propylene glycol in the mass ratio of 1:1. The dye provided by the invention has the characteristics of convenience in use, excellent water decoloring performance, high sticky contamination resistance, and good printing brilliance.