Common heparin is a kind of aminoglucan sulfate extracted from pig intestine mucosa or bovine lung. It is a mixture with a molecular weight range of 3000 ~ 30000KD. Low molecular weight heparin is the fragment of amino glucan sulfate after the cracking of ordinary heparin, and it is also a mixture with a molecular weight range of 3000 ~ 5000KD.

　　Low Molecular Weight Heparin is a general term for a class of Heparin with Low Molecular Weight prepared by depolymerization of ordinary Heparin. So low molecular weight heparin is actually a general name for a class of drugs, including enoxaparin sodium, natron heparin calcium, Dalteparin and so on.

　　Heparin with higher molecular weight can simultaneously bind to antithrombin ⅲ, coagulation factor ⅹ A and coagulation factor ⅱ A, and play the role of anticoagulation factor ⅹ A and ⅱ A. The binding of low molecular weight heparin with antithrombin ⅲ can increase the affinity between antithrombin ⅲ and coagulation factor ⅹ A, and mainly play the role of anticoagulation factor ⅹ A.