TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: Acidified oil is soapstock or oil footings generated during the refining process of rap oil and soybean oil, or the acid hydrolysate of soapstock and oil footings mixture. Preferred Catalysts: Acid catalyst comprises: (1) Amberlyst-15 strong acid cation exchange resin by sulfuric acid (H2SO4) solution dipping treatment; (2) roasted product of dodeca-tungstophosphoric acid (H3PO4.12WO3.xH2O) after H2SO4 solution treatment; (3) series of catalysts prepared from loading H3PO4.12WO3.xH2O on the mixtures of zirconium(IV) oxide (ZrO2), molybdenum trioxide (MoO3), silicon dioxide (SiO2), and/or active carbon by roasting. Preferred Process: Preparing acid catalyst comprises: (1) preparing Amberlyst-15 strong acid cation exchange resin by H2SO4 solution by dipping; dipping the commercial Amberlyst-15 strong acid cation exchange resin in 5-30% H2SO4 solution of equivalent weight for a night, washing with distilled water until there is no sulfate ions (SO42-), drying for a night at 120 degrees C; (2) preparing roasted product of H3PO4.12WO3.xH2O after H2SO4 solution treatment; dipping H3PO4.12WO3.xH2O in 10-30% H2SO4 solution equivalent in weight for a night, filtering, roasting for 1-3 hours at 300-800 degrees C, cooling, grinding; (3) using a series of catalysts prepared from loading H3PO4.12WO3.xH2O on the mixtures of ZrO2, MoO3, SiO2 and/or active carbon by roasting; its preparation method comprises: mixing H3PO4.12WO3.xH2O and carrier by grinding method or dipping method, the grinding method is to uniformly mix the H3PO4.12WO3.xH2O with the mixtures of carriers ZrO2, MoO3, SiO2 and/or active carbon according to a certain weight ratio; the dipping method is to first dissolve H3PO4.12WO3.xH2O in 10- to 15-fold amount of distilled water, dipping with the mixtures of carriers ZrO2, MoO3, SiO2 and/or active carbon for a night, filtering, drying for a night at 120 degrees C, roasting for 1-6 hours at 300-900?OC, reacting, and grinding for use, where mass ratio of H3PO4.12WO3.xH2O and carrier is 0.01-1:1. Preferred Composition: Mass of the acid catalyst is 1-5% of that of the pre-processed oil, and the mass of the basic catalyst is 1.5-2% of that of the esterified product. Mass of methanol in the esterification is 50-100% of that of the pre-processed oil, and the mass of the methanol in the interesterification is 40-65% of that of the esterified product.