OBJECTIVE To study the effect of Puerariae Lobatae Radix on improving coronary microcirculation disorders in ovariectomized rats. METHODS Seventy-two SD female rats were randomly divided into sham-operated group, model group, estradiol valerate group, and Puerariae Lobatae Radix aqueous extract groups(0.8, 1.6, and 3.2 g·kg^-1), and the perimenopausal model of rat was established by bilateral de-ovulation. Two weeks after molding, drugs were continuously administered by gavage for 16 weeks, once a day, and the corresponding dose of saline was given to the sham-operated and model groups. At the end of the 16th week, PowerLab electrophysiological recorder was used to detect systolic blood pressure(SBP), diastolic blood pressure(DBP), mean blood pressure(MBP), left ventricular systolic pressure(LVSP), left ventricular diastolic pressure(LVDP), and maximal left ventricular pressure rising rate (+dp/dt)and maximal left ventricular pressure decline rate(-dp/dt) in the rats. The whole blood high, middle and low shear viscosity, plasma viscosity and hematocrit of rats were detected by blood rheometer. The changes of four items of blood lipid low triglyceride(TG), total cholesterol(TC), high density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol(LDL-C) lactate dehydrogenase (LDH), and creatine kinase (CK) in rat plasma; in plasma of rats were detected by automatic biochemical analyzer. HE staining was conducted to observe the pathological changes in rat myocardium. DiI visualization technology was used to observe the changes in the structure and morphology of coronary microvessels. AngioTool software was applied to analyze the vascular area, density, diameter, the degree of empty space, and according to Poisson Leaf's formula the ion of microvascular resistance to blood flow was calculated. The content changes of nitric oxide(NO) in serum were detected by microtiter method. The content changes of endothelin-1(ET-1) and von Willebrand factor(vWF) in serum were detected by Elisa. Western blot was used to detect the expression of estrogen receptor α(ERα), vascular endothelial growth factor(VEGF) and vascular endothelial growth factor receptor 2(VEGFR2) protein in myocardial tissue. RESULTS Compared with the model group, the water extract of Puerariae Lobatae Radix reduced SBP, DBP, MBP, LVSP and LV±dp/dt max in hemodynamics, whole blood high, medium and low shear viscosity, plasma viscosity and hematocrit in hemorheology, blood flow resistance, myocardial enzyme indexes LDH and CK content, vasoconstrictor factor ET-1 and endothelial injury factor vWF content, and HDL-C content in blood lipid four items, which could reduce inflammatory cell infiltration and myocardial cell atrophy. The contents of TG, TC, LDL-C, blood vessel diameter, area, percentage, porosity, NO content, ERα, VEGFR2 and VEGF protein expression were increased. CONCLUSION Puerariae Lobatae Radix extract can improve coronary microcirculation disorder in ovariectomized rats by regulating endothelial function through estrogen receptor.