Aim To determine the relationship between ambulatory pulse pressure and carotid arteries atherosclerosis in essential hypertension. Methods 172 patients with hypertension were divided into two groups, group A: 24 h mean pulse pressure range from 40 to 55 mmHg. group B: 24 h mean pulse pressure over 55 mmHg. Carotid ultra sonography were also performed to measure intima-media thickness, lumen diameter and plaque. Maximal intima-media thickness(IMTmax) were determined as the index of carotid atherosclerosis severity. Results At the same level of mean arterial pressure (MAP), patients in group B had greater IMTmax and Lumen diameter and higher incidence of plaque than those in group A(P<0.001). Correlation analysis showed that mean pulse pressure, age, mean systolic blood pressure, years of hypertension were post correlated significantly with the IMTmax (r=0.540, r=0.470, r=0.443, r=0.231, allP<0.001), Whereas mean diasystolic blood pressure were negatively correlated with IMTmax (r=-0.28,P<0.05). Multivariate analysis showed that night pulse pressure and age were associated independently with IMTmax. Conclusion Our date showed that ambulatory pulse pressure was the most important Bp parameter during the development of carotid atherosclerosis in hypertension, and it canalso work as a effective index of evaluation severity degree of carotid atheroselerosis.