NOVELTY - Preparing biodiesel using organically modified attapulgite immobilized lipase catalyst, involves (a) pre-treating attapulgite, (b) adding distilled water to the attapulgite, adding quaternary ammonium salt solution, drying and crushing and obtaining the quaternary ammonium salt modified attapulgite, (c) mixing attapulgite and lipase, adding distilled water, leaching and drying product, and (d) adding vegetable oil to dried immobilized lipase, adding methanol, distilling and separating solution to filter glycerin, where final remaining portion is biodiesel.    USE - The method is useful for preparing biodiesel.    ADVANTAGE - The immobilization lipase is used repeatedly for ten times, and the conversion rate is 90% or more.    DETAILED DESCRIPTION - Method for preparing biodiesel using organically modified attapulgite immobilized lipase catalyst, involves (a) adding 1 mol/l dilute sulfuric acid in attapulgite at 30 degrees C, mixing the obtained mixture for 24 hours, washing the obtained product, filtering the obtained product, and drying and crushing the product to obtain pre-treated attapulgite, (b) taking a predetermined amount of the pre-treated attapulgite, adding predetermined amount of distilled water to the attapulgite, stirring the obtained mixture at predetermined temperature, adding predetermined proportion of quaternary ammonium salt solution to the obtained mixture, stirring and reacting the obtained mixture at predetermined temperature for long time, washing and filtering the obtained mixture, drying the obtained product in oven at 110 degrees C, and crushing and obtaining the quaternary ammonium salt modified attapulgite, (c) weighing the attapulgite modified with the quaternary ammonium salt, weighing the lipase, adding the attapulgite and lipase in a three-necked flask, adding distilled water to the obtained mixture, stirring the obtained mixture for 24 hours at room temperature, leaching with a vacuum pump after finishing stirring, removing redundant water, and drying the product in oven at 40 degrees C to obtain the immobilized lipase, and (d) weighing vegetable oil, adding the vegetable oil into the three-necked flask, adding 1-8% dried immobilized lipase to the flask, adding methanol to the obtained mixture, where the molar ratio of methanol and vegetable oil is 3:1, adding the methanol for three times for every 24 hours, reacting the obtained mixture at 30-40 degrees C for 72 hours, recycling the lipase through a suction filter machine, distilling the filtrate, recycling the methanol, separating the solution to filter out the glycerin from the remaining portion, where the final remaining portion is biodiesel.