NOVELTY - Preparing multifunctional methanol-gasoline additive, comprises dispersing tartaric acid in 5-50 times of alcohol in a container, adding acid catalyst with 1-10% of tartaric acid into the container, adding reactant with water into the container and stirring, heating and refluxing the reactant and cooling at room temperature, filtering the reactant to remove solid acid catalyst to obtain the filtrate, washing the filtrate, separating the water solution, adding drying agent to dry organic phase of the water solution, and filtering to remove the drying agent.    USE - The method is useful for preparing multifunctional methanol-gasoline additive.    ADVANTAGE - The method provides additive with good phase stability and reduced saturated steam pressure in a simple manner.    DETAILED DESCRIPTION - Preparing multifunctional methanol-gasoline additive, comprises: (a) dispersing tartaric acid with 5-50 times of alcohol in a container, where tartaric acid is chemical pure or industrial grade acid, and the alcohol is chemical pure or n-amyl alcohol, isoamyl alcohol, hexanol, heptanol, octanol, nonyl alcohol or decyl alcohol; (b) adding acid catalyst with 1-10% of tartaric acid into the container, where the acid catalyst is sulfuric acid, phosphoric acid, polyphosphoric acid, aluminum chloride, ferric chloride, strong-acid cation exchange resin, sodium bisulfate, sulfuric acid, molecular sieve loading zirconium oxide loaded sulfate, ferric oxide loaded sulfuric acid or active carbon loaded sulfuric acid; (c) adding reactant with water and 1-5 times of alcohol into the container, stirring reactant in the container, heating and refluxing at 60-145 degrees C for 4-8 hours, and cooling at room temperature, where the reactant is chemically pure or benzene, toluene, dimethylbenzene, cyclohexane, hexane, ethyl acetate or methyl acetate; and (d) filtering the reaction mixture to remove solid acid catalyst and obtain filtrate, washing the filtrate by 1-10% of sodium carbonate or potassium carbonate aqueous solution, washing to neutral with saturated sodium chloride aqueous solution, and separating the water solution, adding drying agent to dry organic phase of the water solution for 2-12 hours, filtering to remove the drying agent, where the sodium chloride is pure chemical or the reagent with more purity, and the drying agent is anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous calcium chloride or 4A molecular sieve with high purity.