Objective:To obtain the detailed knowledge of aortic root anatomy for reducing complications and selecting device size in chinese patients with catheter aortic valve replacement. Methods:Distances from the aortic annulus (AA) to major landmarks were measured with Dual Source CT(DSCT) at end-systole(ES) and end-diastole(ED) in 34 patients with aortic stenosis (AS) and 39 controls without valve pathology. AA and left ventricular outer tract(LVOT) diameter were assessed in 2 directions by reconstructed coronal and sagittal views. Aortic root and LVOT diameters were also measured with transthoracic echocardiography(TTE). Results:Measurements of left and right coronary ostia height,coronary sinuses height,and sinus of Valsalva(SV) diameter did not differ significantly between controls and AS patients. AS patients had significantly larger diameter of AA,Sino-Tubular Junction(STJ),ascending aorta (AO) and LVOT,larger thickness of interventricular septum (IVS) and larger distance of aorto-mitral continuity fibrous(CF) versus controls(P < 0.01). In all subjects,diameters of AA,SV and STJ,and thickness of IVS were significantly larger in ES than ED(P < 0.05). LVOT diameters were significantly smaller in ES than ED(P < 0.05). AA and LVOT diameters were larger under coronal view than under sagittal views in all subjects. DSCT and TTE methods were significantly correlated for measurement of AA (r = 0.84),SV (r = 0.87),STJ(r = 0.82) and AO(r = 0.82)(All P < 0.05). Conclusion:Aortic root dilatation,LVOT dilatation and elongation,IVS thickness and variable coronary ostial locations present in AS patients. TTE assessment had some limitations. Therefore,DSCT is recommended to select candidates and assess device size to avoid complications.