TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The metal salt chloride is transition metal chloride, preferably anhydrous aluminum chloride, anhydrous platinum chloride, anhydrous ferric chloride, anhydrous manganese chloride, anhydrous chromic chloride, or anhydrous zinc chloride. The base catalyst is potassium hydroxide, sodium hydroxide, sodium silicate, calcium oxide, or magnesium-aluminum hydrotalcite.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The ionic liquor is conventional ionic liquor that is 1-butyl-3-methyl imidazolium p-toluenesulfonate, 1-ethyl-3-methylimidazolium p-toluenesulfonate, 1-butyl-3-methyl imidazolium chloride, 1-allyl-3-methyl imidazolium p-toluenesulfonate, 1-ethyl-3-methyl imidazolium bromide, 1-hexadecyl-3- methylimidazolium bromide, or 1-octadecyl-3-methylimidazolium bromide. The short-chain alcohol is carbinol, ethanol, or propanol. The free fatty acid is stearic acid, oleic acid, linoleic acid, linolenic acid or the mixture of the fatty acids. Preferred Method: The short-chain alcohol recovery is done using reduced pressure distillation. The fatty acid methyl ester and ionic liquor separation is done using quiescence settling lamination or centrifugal separation. The recovered ionic liquor after being dried is taken as the catalyst of the alcoholization reaction continuously. The molar ratio of the mixture is 0.01:0.1:5-10.1. The alcoholization reaction is done at 60-90 degrees C for 30-120 minutes. The molar ratio of the mixture of ionic liquor to metal salt chloride is 1:1-9. The short-chain alcohol is recovered after the alcoholization reaction. The mixture of reacted fat and fatty acid methyl ester is separated from the ionic liquor and is used in the ester exchange reaction. The recovered ionic liquor is dried. Base catalyst (0.5-5%) is added into the mixture of fat and fatty acid methyl ester. The mixture of short-chain alcohol and fat is added into the short-chain alcohol at a molar ratio of 5-10:1 and reacted at 60-80 degrees C for 30-120 minutes. Quiescence laminating the reactant is conducted. The upper phase contains the bio-diesel and short-chain alcohol. The middle phase contains glycerol, base catalyst, soap, and short-chain alcohol. The lower phase is ionic liquor. The short-chain alcohol with the upper phase liquor is recovered via vacuum distillation, and washed with 70-90 degrees C of hot water to make water clean. The high acid value oil is illegal cooking oil, waste oil, vegetable oil leftovers, or pressed jatropha oil.