Three cellulose sulfates (CS) with their sulfate groups only at C-6 position (CSC6)

only at C-2position (CSC2)

and at some C-6 & C-2 positions (CSC6

2) were prepared respectively by the direct sulfation method and the regioselective sulfation method. To reveal the structure-activity relationship between sulfate groups and anticoagulation activities of CS

their anticoagulation activities were investigated by measurement of coagulation time and coagulation factor activity assays. It was indicated that CSC6

2 could significantly prolong thrombin time (tTT) and inhibit the activity of coagulation factor Ⅱa

also CSC2 had a pronounced activity of prolongation of activated partial thromboplastin time (tAPTT) and inhibition of the coagulation factorⅩa. Comparatively the anticoagulation activity and the inhibition of the coagulation factors of CSC6 were weaker than those of CSC6

2 or CSC2. The site of the sulfate groups in CS influnced the flexibility and conformation of the glycan chains

resulting in the different affinity of CS and antithrombin Ⅲ (AT Ⅲ).Thus

the prolongation of tAPTT& tTT and the inhibition of Ⅱa & Ⅹa of CS was associated with the site of the sulfate groups in CS.