Objective To investigate the correlation between plasma von Willebrand factor(vWF) and the extent of coronary artery lesion in acute coronary syndrome (ACS).Methods One hundred and forty eight ACS patients (ACS group) who performed coronary angiography (CAG) were divided into single stenosis group (54 patients),double stenosis group (51 patients) and multitude stenosis group (43 patients) by the number of stenosis through CAG.They were divided into mild group (Gensini score ≤ 20 points,31 patients),midrange group (Gensini score 21-40 points,47 patients) and severe group (Gensini score ≥ 41 points,70 patients).Fifty patients with stable angina pectoris (SA) were randomly selected and classified as SA group,while 50 patients with healthy coronary were randomly selected as control group.Blood sample of 248 patients were collected to detect the level of vWF,and blood routine examination,blood clotting function,liver and renal function,high sensitivity C-reactive protein (hs-CRP),blood glucose,blood fat were detected.The correlation between vWF and the extent of coronary artery lesion were analyzed.Results The level of white blood cell count (WBC) and hs-CRP in ACS group were significantly higher than those in SA group and control group (P ＜ 0.05).But the level of WBC and hs-CRP between SA group and control group had no significant difference (P ＞ 0.05).The level of blood platelet count,prothrombin time,partial prothrombin time,fasting blood glucose,thrombin time,2 h postprandial glucose,triglyceride,total cholesterol had no significant difference among three groups (P ＞ 0.05).The level of vWF in ACS group was significantly higher than that in SA group and control group [(143.25 ± 20.42)％ vs.(102.77 ± 11.84)％,(97.63 ± 10.31)％] (P ＜0.05).The level of vWF in single stenosis group,double stenosis group and multitude stenosis group was (127.34 ± 9.35)％,(144.81 ± 12.02)％,(159.55 ± 18.62)％,and significantly higher than that in control group (P ＜ 0.01).The level of vWF in mild group,midrange group and severe group was (124.77 ± 14.31)％,(132.53 ± 16.38)％,(155.06 ± 18.53)％,and significantly higher than that in control group (P ＜ 0.01).The level of vWF had significantly positive correlation with the number of stenosis and Gensini score (r =0.698,0.683,P ＜ 0.01).Conclusion The level of vWF in peripheral blood is closely related with the severity of ACS and has important clinical significance in evaluating the condition and guiding therapy in patients with ACS.