Aim To study the relationship between serum uric acid(SUA) and coronary artery disease(CAD),and try to explain the relationship between them by observing the effect of uric acid on vascular smooth muscle cells(VSMCs) of SD rats. Methods The basic informations(fast blood fat,glucose,uric acid and body mass index,et al) of 368 in-patients undergone coronary artery angiography were collected.Uric acid levels were compared among patients with different degree of coranary lensions,and Logistic regression was applied to analyze the relationship between serum acid level and degree of coronary lensions.Vascular smooth muscle cells were cultured with attachment blook method.Different concentrations of uric acid were applied to culture together with them for 48 hours,and the vital force of VSMCs was detected and compared. Results Levels of SUA were higher in male patients and in patients with CAD,and were relatively higher in patients with three coronary arteries lesions and in patients with coronary lesion score over 15.Taking coronary lesion score as dependent variable,SUA level didn't enter regression equation.Effects of different concentrations of uric acid on VSMCs weren't statisticly different. Conclusions Serum uric acid isn't an independent risk factor of CAD.Uric acid have no definite effects on VSMCs of rats.