Aim To establish a new model of coronary microthrombosis model in rats. Methods A total of 87 male Sprague-Dawley rats were used in this study. Rats were anesthetized with ketamine and devided into sham group (n=6),sodium laurate group (n=54) and microspheres group (n=27). In sodium laurate (SL) group, 200 μg of sodium laurate was injected into the coronary artery while in microspheres (MS) group, different amount of microspheres (42 μm in diameter) were injected into the coronary artery, the sham group was injected saline instead. The thrombus induction and consequent of myocardial dysfunction were examined by histopathological analyses and non-radiactive microspheres. Results One hour after SL injection, there is microthrombus in coronary artery and reaches a peak three hours after the injection (66.4%±18.8%). Microscopic examination of Carstairs Stain sections (n=8) revealed that microthrombi containing fibrin strands obstructed the perforating arteries in the myocardium. Multiple small myocardial infarcts were observed in the heart. Multiple microinfarctlets were observed and a more severe inflammatory reaction was seen in SL group. LVEF was also decreased in SL group which is comparable to the injection of 1000 microspheres. Conclusions Coronary microthrombosis model was successfully induced after injection of SL into the coronary artery. The model is useful for the investigation of the pathophysiology of coronary microthrombosis.