To explore the thoracic ascending aortic （TAA） pathophysiological characteristics of heterozygous mutant 11 mice under the norepinephrine-induced hypertension mode.Female heterozygous mutant 11 and wild type 11 mice were selected as experimental group (HET group) and control group (WT group)，respectively. The hypertensive model was induced by intraperitoneal injection of norepinephrine (NE)，and TAA diameter and invasive blood pressure (Bp) data were collected dynamically in real time using high-frequency ultrasound imaging and invasive arterial blood pressure monitoring technique，so as to indirectly analyze TAA compliance of two groups of mice. At the same time，the incidences of hemothorax and TAA rupture were further analyzed by autopsy and histology.After injection of NE，heterozygous mice did not show a higher Bp increase percentage in systole or diastole comparing with wildtype mice. However，heterozygous mice exhibited 17% and 32% higher TAA diameter dilation percentage than wildtype ones in systole and diastole respectively. Two heterozygous mice had TAA dissection and rupture，and the incidence of hemothorax in heterozygous mice (3/5) was higher than that in wildtype (0/5).It was very likely that the altered TAA wall compliance of mutant 11 mice had led to a higher TAA dilation degree than that in wildtype，and even could be the potential reason of TAA dissection and rupture.