NOVELTY - Producing bio-diesel comprising oil foot acidification oil of plant oil, animal oil, hogwash oil and waste oil as raw materials comprises: (a) oil non-catalyzed high pressure hydrolysis; (b) fatty acids gaseous phase esterification; (c) neutralization, dehydration and water washing; and (d) fatty acids methyl ester high vacuum continuous distillation.    USE - Process for producing biodiesel (claimed). It is also useful for industrial production.    ADVANTAGE - The invention has a short reacting time, high raw material conversion rate, low producing cost, and stable product quality.    DETAILED DESCRIPTION - Producing bio-diesel comprising oil foot acidification oil of plant oil, animal oil, hogwash oil and waste oil as raw materials comprises: (a) oil non-catalyzed high pressure hydrolysis: sending raw material and water into high effective hydrolysis tower, keeping pressure at 1.5-2.0 Mpa, controlling temperature at 210-230 degrees C, the raw material is generated into black fatty acids and glycerol via heating and hydrolysis; (b) fatty acids gaseous phase esterification: leading the black fatty acids obtained in (a) and 14wt.% methanol and 1.5-2.5wt.% acid catalyst into esterification kettle, controlling temperature at 100-110 degrees C, performing gaseous phase esterification reaction, generating rough fatty acids methyl ester; (c) neutralization, dehydration and water washing: joining 2wt.% alkali and water into the rough fatty acids methyl ester obtained in (b), then sending into neutralization kettle, to neutralize the surplus acid of esterification reaction, water dehydrating the surplus methanol and water washing the rough fatty acids methyl ester; and (d) fatty acids methyl ester high vacuum continuous distillation: sending the rough fatty acids methyl ester via neutralization, alcohol removing and water wash in (c) into ester vacuum distillation tower, pre-heat at 210-230 degrees C, adopting membrane evaporator that the pressure is -0.3 Mpa to distil, the fatty acids methyl ester after distilling (bio-diesel) is distilled from the middle of the tower, the tower bottom obtaining asphalt, tower top recycling to obtain front fraction.