NOVELTY - Wet algal biomass is microwave-reacted with chloroform, methanol, and concentrated sulfuric acid. The liquid is then centrifuged, lower algal residue is separated, and the upper oil phase is pipetted out. The oil phase is added with water and centrifuged, and the lower oil phase is pipetted out. The oil phase is added with water and centrifuged, and the lower layer of oil phase is pipetted out. The resulting oil is finally oven-dried at 85 degrees C to obtain biodiesel. The algal residue is further processed to obtain bio-crude oil.    USE - Grading of wet algal biomass by preparing different grades of bio-oil (claimed).    ADVANTAGE - The method provides biodiesel oil having a simple composition, with carbon and hydrogen content being the highest. The biodiesel oil is easy for subsequent use.    DETAILED DESCRIPTION - Wet algal biomass is filtered, pressure-filtered or centrifuged to remove moisture and reduce the moisture content from 90% to 10%. 1-100 g Wet algal biomass is added to a microwave digestion tank, followed by addition of 10-100 mL chloroform, 10-100 mL methanol, and 0.25-25 ml 98 %mass concentrated sulfuric acid, and microwave treatment is carried out. The liquid is then transferred from microwave digestion tank to a centrifuge tube, the digestion tank is washed twice with 5-50 ml chloroform, and the liquid from the tank is transferred to the centrifuge tube. The algal liquid is centrifuged at 4000 rpm for 5 minutes, lower algal residue is separated, and the upper oil phase is pipetted out. Microwave treatment is carried out at 50-80 degrees C and 915 MHz or 2450 MHz for 10-30 minutes. The resulting oil phase is added with 10-100 mL water and centrifuged at 4000 rpm for 5 minutes, and the lower oil phase is pipetted out. The oil phase is added with 15-150 ml water and centrifuged at 4000 rpm for 5 minutes, and the lower layer of oil phase is pipetted out. The resulting oil is finally oven-dried at 85 degrees C to obtain biodiesel. The algal residue is washed thrice with 10-100 mL methanol to remove chloroform, and then thrice with 10-100 mL deionized water to remove methanol. The obtained algal residue is added to a reactor, followed by addition of 90-900 ml deionized water. Nitrogen is supplied to the reactor for 3-5 minutes to remove air inside the reactor. The reactor is heated at 300 degrees C for 30-40 minutes and then cooled at 50-70 degrees C for 50-80 minutes, while stirring at 180 rpm, without adding a catalyst. Bio-oil is extracted from the reactor by addition of 20-200 ml chloroform. The reactor is washed 5 times with 10-100 mL chloroform, and the resulting chloroform extract is centrifuged at 4000 rpm for 5 minutes. The upper oil phase is pipetted out and oven-dried at 85 degrees C to obtain bio-crude oil.