Aim To investigate the association between von Willebrand factor (vWF) and the numbers of coronary artery stenotic lesions in acute coronary syndrome. Methods The concentration of plasma vWF was measured by enzyme linked immuoserbent assay (ELISA) in 54 patients with acute coronary syndrome and 15 stable angina pectoris and 20 normal persons without any angiographically detectable coronary artery disease. The relationship between plasma vWF level and the number of coronary vessels with stenosis was assessed. Results The concentrations of plasma vWF in patients with acute coronary syndrome were significantly higher than those in patients with stable angina pectoris (p<0.05) or control subjects (p<0.05). The level of plasma vWF was obviously higher in the multiple-vessel groups than in the single-vessel group (p<0.05), and the concentration of plasma vWF was positively related to number of vessels with percent stenosis of >50% diameter (r=0.224, p<0.05). Conclusions The vWF level, which is an indicator of thrombogenesis and endothelial damage, was significantly increased in patients with acute coronary syndrome. It is an indicator of distinguishing and predicting acute coronary instability and it is influenced by the degree of coronary atherosclerosis.