Objective Apply real-time three-dimensional transesophageal echocardiography (RT-3D-TEE) in aortic regurgitation(AR) patients to quantitatively analysis the aortic root anatomical characteristics and screening the parameters which significantly affect AR to further reveal the mechanism of AR and provide clinical more information. Methods 42 patients with AR were enrolled as AR group and 30 cases of non-AR people were involved as control group. RT-3D-TEE was using to collect images in two groups and offline analysis was performed. 3 sets of parameters of the aortic root : root diameter (AAD、SOVD、STJD) ; root area (AAA、SOVA、STJA) ; root circumference (AAC、SOVC、STJC) were acquired. Parameters of two groups were compared, and the parameters were incorporated into the logistic regression model, then the ROC curves were obtained. Results ①Compared with the control group, SOVD、STJD、AAA、SOVA、STJA、AAC、SOVC、STJC in AR group increased (P＜0.05),while the rest parameters had no statistical differences (P＞0.05)；② Multivariable logistic regression model gradually screening of the significant factors influencing the reflux, and as a result STJA and STJC had significant influence on AR, P values were 0.002、0.005；③ The ROC curve analysis showed that the area of STJA or STJC curve were both greater than 0.5, which were 0.867 and 0.885 separately. Conclusions In AR patients, parameters in three levels of aortic root-aortic annulus, sinus of valsava and sinus tube junction- increased differently. The area and circumference of the sinus tube junction changed significantly, and this might be one of the possible mechanism of AR.