The invention relates to a comprehensive utilization method of wastewater from a sausage casing factory. Composition of wastewater produced in each link of the technological process from treatment ofsmall intestines of a pig to extraction of fine heparin sodium is analyzed and comprehensively utilized. According to the method, waste liquor containing heparin sodium and sodium chloride is recycledafter extraction of heparin sodium. Other organic matter such as protein, fat and the like is emulsified into a group with a hydrophobic inner layer and a hydrophilic outer layer by an added compoundemulsifier, the dispersion effect of the organic matter in a liquid is improved, then a small amount of calcium chloride-ferric chloride or calcium chloride-zinc chloride is added, aggregative deposit is generated and deposited by an added flocculating agent, and diluent brine is obtained after treatment and recycled. Raw material use ratio is increased, the waste liquor can be comprehensively utilized, a sodium chloride solution is recycled particularly, and the problem that the wastewater is difficult to treat due to high sodium chloride content is solved, so that the wastewater treatment amount is reduced greatly. National policies and guidelines for resource utilization, energy conservation, emission reduction and environmental protection are met.