The invention discloses a method for preparing an economic environment-friendly disperse dyestuff, belonging to the technical field of the textile chemical industry. According to the invention, a proper dye composition is designed through selection of disperse dyestuffs which do not contain aromatic amine, chlorine substituent and the like that may produce aromatic amine and chlorophenol structures during preparation and application, study on the compatibility, synchronous dyeing degree, substantivity, absorption rate and other indexes of the disperse dyestuffs, and further analysis on the color change and color inconstancy of compounded dyestuffs of different color systems. Environment-friendly auxiliary agents with low toxicity, low formaldehyde content or no formaldehyde and high degradation performance are compounded with the selected appropriate dyestuffs, so the prepared disperse dyestuff has synergistic effect, is environment-friendly and highly efficient and lowers dyeing cost.