von Willebrand factor(vWF) is a high molecular weight multimeric glycoprotein and is absent or abnormal in von Willebrand disease (vWD).The essential information for its function resides in the monomer. vWF participates in thrombosis and haemostasis through interacting with GPⅠb.GP Ⅱb-Ⅲ a,collagen,FⅧ and heparin.