Aim To explore the effect of Baicalin on blood pressure and left ventricular remodeling in rats with renal hypertension. Methods Amogn 40 male Wistar rats 10 were randomly selected for sham operation group, which renal hypertensive rat model was established by using two kidney one clip method. The rats with renal hypertension were randomly divided into model group and Baicalin group after 6 weeks, eventually alive rats were devided into sham operation group (n=9), model group (n=10) and Baicalin group (n=11) for 4 weeks intervention. During the experiment, the general situation of rats was observed, and the blood pressure were detected before operation, operation after 6 weeks, and intervention for 4 weeks; high frequency echocardiography were detected after 4 weeks and the cardiac function indexes were measured. The rats were sacrificed and the heart was removed. The morphological changes of myocardial tissue was observed by using HE staining, Masson staining. The myocardial apoptosis was detected by TUNEL method and the expression of endoplasmic reticulum chaperone glucose regulated protein(GRP78), glucose regulated protein(GRP94) in myocardial cell of rats were also detected by real-time PCR and Western blot. The expression of CCAAT/enhancer binding protein homologous protein(CHOP) and Caspase 3 was monitored by Western blot. Results Compared with model group, there was significant change of blood pressure in Baicalin group (P<0.05), and the indexes of left ventricular remodeling were significantly improved after the echocardiography(P<0.05). Compared with model group, the integral of pathological myocardial fibrosis and fibrosis related factors matrix metalloprotein-9(MMP-9), matrix metalloprotein-2(MMP-2), connective tissue growth factor(CTGF) and transforming growth factor-β1(TGF-β1) expression was significantly decreased in Baicalin group(P<0.05). Compared with model group, the expression of GRP78, GRP94, CHOP, Caspase 3 and apoptosis of cardiomyocyte were significantly decreased in Baicalin group(P<0.05). Conclusion Baicalin had a certain antihypertensive effect, it could improve the left ventricular remodeling in renal hypertensive rats, reduce myocardial pathological changes, ease the endoplasmic reticulum stress and reduce apoptosis in myocardial cell.