The invention relates to an application of sorghum red pigment, an aqueous coloring agent and a preparation method thereof and aqueous wood lacquer. The aqueous coloring agent comprises, by weight, the following raw materials: 10-45 parts of sorghum red pigment, 20-51 parts of water, 0.1-1 part of preservative, 0.5-1 part of hue stabilizer and 0.1-2 parts of viscosity stabilizer; the pH value of the aqueous coloring agent is 7-10. Not only has the aqueous coloring agent a good color rendering property in aqueous resin, but also the most stable coloring pH value range of the color phase of thesorghum red pigment is matched with the neutral and slightly alkaline pH value range of the aqueous resin, the coloring capacity is strong, the color of the paint film is fresh, bright, transparent after being colored by using the coloring agent, the coloring agent has the advantages of good light resistance, heat resistance, and chemical resistance, has no toxicity and harmlessness, can achieve the coloring effect of metal complex dyes, and can avoid the environmental protection and safety problems of heavy metal ions and organic volatiles caused by metal complex dyes.