The preventive effect of Malus leaves extract in a model of L-NNA-induced hypertension mice was investigated in this study. The systolic blood pressure (SBP), i.e. the blood pressure (MBP) and diastolic blood pressure (DBP) in hypertensive mice were reduced by treatment with Malus leaf extract. After treatment of hypertension mice with Malus leaf extract, the levels of nitric oxide (NO) in the serum, heart, liver, kidney, and stomach of the mice were higher than those in the model group, while the levels of malondialdehyde (MDA) were lower than those in the model group. The serum levels of endothelin-1 (ET-1), vascular endothelial growth factor-A (VEGF-A), E-selectin were decreased, but the level of calcitonin gene related peptide (CGRP) was increased in hypertension mice treated with Malus leaf extract. The mRNA expression of heme oxygenase-1 (HO-1), neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS) and receptor activity modifying protein 2 (RAMP2) in heart and vascular tissues of hypertensive mice were up-regulated, and the expressions of adrenomedullin (ADM), and inducible nitric oxide synthase (iNOS) d were down- regulated by Malus leaf extract. The results showed that Malus leaf extract contain hyperoside, isoquercitrin, dihydroquercetin, quercitrin, hesperidin, myricetin, isobaicalin, neohesperidin dihydrochalcone and quercetin, and the contents were 104.92, 83.05, 15.14, 242.83, 60.24, 13.87, 125.53, 11.23 and 28.92 mg/g, respectively. Meanwhile high concentration of Malus leaf extract had better preventive effect, which was close to the hypertension drug captopril. These results suggest that leaves of Malus leaf have a good preventive effect on experimental hypertension.