NOVELTY - Oil-containing plant material is crushed, sealed in a bag, and placed in Soxhlet extraction apparatus, lower alcohol, promoting solvent and catalyst are added, stirred and heated. The lower alcohol and promoting solvent are volatilized, extracted and cooled. The extracted product is removed, evaporated in water bath, washed with water, upper layer containing biodiesel and lower layer containing glycerol are separated, and the upper layer is repeatedly washed with water to obtain biodiesel.    USE - Extraction of biodiesel using Soxhlet apparatus (claimed).    ADVANTAGE - The method enables extraction of biodiesel with reduced energy consumption and without performing deacidification, degumming, dephosphorization and dewaxing, within a short period of time, by simple, safe and economical process.    DETAILED DESCRIPTION - Oil-containing plant material is crushed, sealed in a bag, and placed in Soxhlet extraction apparatus, lower alcohol, promoting solvent and catalyst are added, stirred and heated. The lower alcohol and promoting solvent are volatilized, extracted and cooled for 2-24 hours. The extracted product is removed, evaporated in water bath at 30-60 degrees C and vacuum of 0.01-0.1 MPa such that the unreacted alcohol and promoting solvent are evaporated. The resulting mixture is washed with water, upper layer containing biodiesel and lower layer containing glycerol are separated, and the upper layer is repeatedly washed with water to obtain biodiesel. The oil-containing plant material is rapeseed, soybean, peanuts, pistache seed, pepper seed, cottonseed, Xanthoceras sorbifolium, jatropha seeds, rubber seed, or castor beans. The lower alcohol is methanol and/or ethanol. The volume ratio of oil-containing plant material and alcohol is 1g:5ml-1g:20ml. The promoting solvent is toluene, n-hexane, n-pentane, petroleum ether, cyclic ether, tetrahydrofuran, methyl acetate, ethyl acetate, diethyl ether or methyl tert-butyl ether. The volume ratio of lower alcohol and promoting solvent is 2:1-6:1. The catalyst is sodium hydroxide, potassium hydroxide, sodium methoxide, concentrated sulfuric acid, ferric sulfate or sodium bisulfate. The amount of catalyst is 0.2-10 %mass.