NOVELTY - Preparation of photosynthetic bacteria using biogas anaerobic culture involves: preparing seed culture medium, preparing liquid culture medium using seed culture and biogas slurry; adding oscillation culture box to culture for 4-7 days to obtain bacterial liquid; adding bacterial liquid to liquid culture medium in volume ratio of 20-30%, and then the light intensity is 400-2000 lux, rotating speed is 10-20 rpm with temperature of 25-35 degrees C, shaking culture box to culture for 3-4 days to finish.    USE - For preparation of photosynthetic bacteria (claimed) in organic waste water processing field.    ADVANTAGE - The photosynthetic bacteria number reaches 40 billion/ml, can reach 70-80% by the removing rate of the biogas liquid COD and removing bacteria, can be used as feed additive, and can effectively remove the organic matter, nitrogen, phosphorus and sulfide in the waste water, which is applied to organic waste water processing field.    DETAILED DESCRIPTION - Preparation of photosynthetic bacteria using biogas anaerobic culture involves: weighing sodium acetate (3-4 g), sodium propionate (0.2-0.4 g), sodium chloride (0.1-0.3 g), ammonium sulfate (0.1-0.5 g), magnesium sulfate (0.1-0.3 g), monopotassium phosphate (0.5-0.8 g), potassium dihydrogen phosphate (0.2-0.5 g), calcium chloride (0.05-0.15 g), and yeast extract (0.1-0.3 g) and orderly adding water (100-150 ml) to uniformly mixing, then carrying out high temperature sterilization to obtain seed culture medium; diluting biogas slurry to COD 9000-10000, then adding sodium acetate (1-2%) to obtain liquid culture medium; biogas residue cow dung as raw material obtained by fermentation using dairy manure biogas slurry to obtain biogas fluid; inserting in seed culture medium, Rhodopseudomonas palustris pseudomonas with illumination intensity of 400-2000 (preferably 1000) lux, rotating speed of 10-20 (preferably 20) revolution per minutes (rpm), temperature of 25-35 (preferably 28) degrees C, adding oscillation culture box to culture for 4-7 (preferably 5) days to obtain bacterial liquid; adding bacterial liquid to liquid culture medium in volume ratio of 20-30%, and then the light intensity is 400-2000 lux, rotating speed is 10-20 (preferably 10) rpm with temperature of 25-35 (preferably 30) degrees C, shaking culture box to culture for 3-4 (preferably 4) days to finish.