1. Heparin was originally proposed from the liver, but is now mostly extracted from the intestinal mucosa of pigs, sheep, cattle and other animals, and can be extracted from the lungs and liver. Put fresh intestinal mucosa into the reaction pot, add sodium chloride at 3% and adjust pH to 9.5 with 40% sodium hydroxide. The temperature was gradually raised to 60-65℃ within half an hour, and the mixture was continued for 2h. Then the temperature was raised to 95℃ and maintained for 10min. The temperature was cooled to below 50℃ and filtered. The strongly basic quaternary ammonium salt anion resin was added into the filtrate, stirred and adsorbed for 8 hours, and left to percolate. The next day, siphon off the supernatant, rinse the resin with water to clarify the supernatant, drain it, stir with 2 times 1.4m sodium chloride for 2 hours, drain it, and wash the resin once again without 1.4m sodium chloride. Then, the resin was eluted twice with 3M sodium chloride and drained. The filtrate was merged, and an equal amount of 95% ethanol precipitation solution was added. The precipitation was collected, dehydrated and dried with acetone to obtain coarse products. Crude products dissolved in 1% sodium chloride, with hydrochloric acid adjust pHGCF 1.7-1.8, filtration. Adjust pH to 11 with 5N sodium hydroxide, add 30% concentration hydrogen peroxide decolorization, filtration. Adjust the pH of filtrate to 6 with hydrochloric acid, and add equal amount of 95% ethanol precipitation. Sink the content with acetone catharsis, dry, it is heparin namely.

　　2. Enzyme-resin method

　　3. Salinization - resin method