NOVELTY - Methanol-diesel fuel contains diesel fuel, methanol, cyclic aromatic hydrocarbon, alkyl acid, naphthenic acid, and lipophilic alcohol-dispersed polymer with specified relative density. Preparation of a small model sample involves mixing methanol, cyclic aromatic hydrocarbon, uniformly stirring, standing to separate hydrocarbons from precipitate, discarding precipitate, measuring relative density in which apparent density difference from paraffinic diesel is due to incompatibility in affinity of methanol, cyclic aromatic hydrocarbon, naphthenic acid, and adjusting B and C.    USE - Methanol-diesel fuel (claimed).    ADVANTAGE - Methanol diesel blend is heavy duty fuel with good fluidity and fire resistance, is suitable for low-temperature use, and preparation is simple, safe, energy saving, environment-friendly, and lowers production cost.    DETAILED DESCRIPTION - Methanol-diesel fuel contains 60-86 vol.% diesel fuel, 10-34 vol.% methanol, 2-20 vol.% cyclic aromatic hydrocarbon, 0-2 vol.% alkyl acid, 0-3 vol.% naphthenic acid, and 0.1-0.2 vol.% lipophilic alcohol-dispersed polymer. Methanol-diesel fuel has relative density at 20 degrees C which is same as relative density of paraffinic diesel and raw materials follow the equation (Ad1+Bd2+Cd3+Dd4+Ed5)/100=K in which raw material values are accurate to the thousandths, 100 is total volume of formulation and A+B+C+D+E=100 is expressed in same unit and has uniform temperature, relative density value of formulation is greater than or equal to K value, and lipophilic alcohol-dispersed polymer is negligible where, A is volume of diesel, d1 is relative density of diesel at 20 degrees C, B is volume of ethanol, d2 is relative density of methanol at 20 degrees C, C is volume of cyclic aromatic hydrocarbon, d3 is relative density of cyclic aromatic hydrocarbon at 20 degrees C, D is volume of alkyl acid, d4 is relative density of alkyl acid, E is volume of naphthenic acid, and d5 id relative density of naphthenic acid, and K is relative density of paraffinic diesel, d1, d2, d3, d4, and d5 is accurate to the thousandths, and relative density values of d3, d4, and d5 is greater than or equal to relative density of K. Preparation of a small model sample involves mixing 10-30 vol.% methanol, 2-10 vol.% cyclic aromatic hydrocarbon, uniformly stirring, standing to separate hydrocarbons from precipitate, discarding precipitate, measuring relative density in which apparent density difference from paraffinic diesel is due to incompatibility in affinity of methanol, cyclic aromatic hydrocarbon, naphthenic acid, adjusting B and C by resolving equation and multiplying C with its relative density where, C, A, D, and E have specific volume based on raw material supply, K and d1 is measurable, d2, d3, d4, and d5 have known values, B and C values can be resolved using the equation in which C is volume of solid, and stirring solid in lipophilic alcohol-dispersed polymer to prevent deposition of stable hydrocarbon layer in which cyclic aromatic hydrocarbon is benzoic acid, benzaldehyde, ethyl benzoate ester, terephthalic acid, naphthenic acid, or aniline and polymer dispersed in lipophilic alcohol is starch or polyvinylpyrrolidone.