1. Clean fresh pork lungs (or frozen pork lungs after natural thawing) with clean water to remove internal and external dirt and skin fat, grind them into a paste, stir them thoroughly, add equal amount of water, and add a little preservative with a solubility of.01%. Mix well.

　　2. Enzymatic hydrolysis and extraction: firstly, stir the above materials fully and adjust the PH value to 8-9 with a small amount of dilute alkali solution. Then add the freshly chopped pancreatic juice as the enzymatic hydrolysis agent, stir well, and slowly heat up to about 40 ° c.

　　Continue to stir and maintain the feed solution PH=7.5-8, maintain the solution temperature at 37-40 ° c for 3-4 hours, then heat up to 47-50 ° c, maintain the PH value of 8.0-8.5, and add a little pig pancreatic juice as appropriate, continue the enzymatic hydrolysis for 4-5 hours.

　　3. Ion exchange adsorption; Firstly, the extract of the above enzymatic hydrolysis was cooled to room temperature, carefully removed the oil thin layer floating on the liquid surface, controlled the temperature rise to 45 degrees, stopped the heating, and added heparin sodium components in the prepretreated d-254 resin and effective adsorbent liquid under agitation.

　　4. Refining: the obtained heparin sodium crude product was completely dissolved with 2% sodium chloride solution to make a solution with a solubility of about 8%. In this process, the temperature could be appropriately raised to help the solution. The above feed was finely adjusted with 5mol/L sodium hydroxide solution at a PH of 8.0-8.2 and heated to 78-80 ° c.

　　The precipitate is dehydrated by anhydrous ethanol, ground up, dehydrated by acetone, ground up, dehydrated by acetone, far infrared ray vacuum drying (50-60 degrees), then heparin sodium is obtained.