NOVELTY - Culturing oil producing microalgae using fecal sewage, comprises e.g. separating solid-liquid of fecal sewage, flocculating and dewatering the solid-liquid, carrying out aerobic composting process, anaerobic treatment, aerobic treatment, membrane biological reaction and odor treatment on the solid-liquid to obtain a non microorganism liquid, where the liquid has a suspended substance of less than 3 mg/l, and a pH of 6-9, adding microalgae culture liquid into the liquid to obtain marsh gas, and collecting the marsh gas.    USE - The method is useful for culturing oil producing microalgae.    ADVANTAGE - The method provides microalgae in a simple and cost-effective manner.    DETAILED DESCRIPTION - Culturing oil producing microalgae using fecal sewage, comprises: (a) separating solid-liquid of fecal sewage, flocculating and dewatering the separated solid-liquid, carrying out aerobic composting process, anaerobic treatment, aerobic treatment, membrane biological reaction and odor treatment on the separated solid-liquid to obtain a non microorganism liquid, where the liquid has a suspended substance of less than 3 mg/l, a pH of 6-9, ammonia nitrogen content of 30-35 mg/l, and phosphorus content of 1-6 mg/l, adding microalgae culture liquid into the liquid to obtain marsh gas, and collecting the marsh gas; (b) inoculating oil-producing microalgae into 5 conical flasks filled with 2 l of F/2 culture solution, shaking the mixture, where the microalgae strain has an initial density of (200-300) x 104 cell/ml, inoculating microalgae strain in the F/2 culture solution in a volume ratio of 4-6, conducting amplification culture at 22-26 degrees C and at light intensity of 1800-2000 lux in a ratio of illumination period to dark period of 14:10 hours, sending carbon dioxide gas into the conical flask for every 6-8 hours when the concentration of the microalgae in the conical flask reaches (20-100) x 104 cell/ml to obtain an amplification cultivated microalgae solution, transferring the amplification cultivated microalgae solution in the conical flasks to a first biological reactor filled with the non microorganism liquid to conduct domestication culture after amplification culture is completed using the microalgae solution and the microalgae in the first biological reactor in a volume ratio of 1:1-1:4, performing domestication culture at 22-26 degrees C and at light intensity of 1800-2000 in a ratio of illumination period to dark period of 14:10 hours, passing carbon dioxide into the biological reactor for one time of every 6-8 hours, where the carbon dioxide has a ventilation rate of 3-6 l/minute, and ventilation time of 5 minutes, allowing the microalgae to adapt with the culture solution after 1-2 days of the domestication culture and allowing the microalgae to reproduce and grow, where the culture solution is a microalgae solution; (c) placing the obtained microalgae solution in a second biological reactor, where the second biological reactor has a volume of 50 ml, keeping the microalgae solution at 22-26 degrees C and at illumination intensity of 2500-4000 lux in a ratio of illumination period to dark period of 14:10 hours, and passing carbon dioxide into the second biological reactor for one time of every 6-8 hours, where the carbon dioxide has a ventilation rate of 3-6 l/minutes, and a ventilation time of 5 minutes; (d) placing the microalgae solution to a third biological reactor, where the third biological reactor has a volume of 50 ml, a ratio of illumination period to dark period of 16-8 hours, and illumination intensity of 6000-8000 lux, and the carbon dioxide has a ventilation rate of 1-3 l/minutes, sending carbon dioxide to the third biological reactor for 5 minutes of every 3-4 hour after culturing for 3-5 days, where the microalgae solution has a concentration of 97.5-98%, and returning 2-2.5% of the microalgae solution to conduct microalgae amplification culture; (e) sending the microalgae solution into a membrane reactor using a delivery pump, where: the membrane reactor is installed with an ultrafiltration membrane; and a carbon dioxide ventilate pipe is arranged below the ultrafiltration membrane, entering the microalgae solution into the ultrafiltration membrane using an aperture, and discharging the solution through a center of the ultrafiltration membrane, concentrating the solution in the third reactor, filtering the concentrated solution using the ultrafiltration membrane, and sending the filtered solution into the membrane reactor under action of the carbon dioxide to remove attached matter on a surface of the ultrafiltration membrane, where the liquid in the membrane reactor is divided into two parts using 10-20% of the concentrated solution, and 80-90% of the concentrated solution returns to the third biological reactor to culture and to improve the absorbance of the microalgae; and (f) placing the concentrated liquid into a centrifuge machine under a speed of 6000 rpm, and collecting and baking the collected microalgae at 80-110 degrees C for 12 hours to obtain microalgae with a specific gravity of 0.4-0.75 g/l , where the microalgae has a total fat content of 20-30%, and the carbon dioxide is present at 6-8%.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a method for culturing oil producing microalgae.