Objective This study aimed to investigate the structure of the mitral valve in patients undergoing mitral valvuloplasty (MVP) using real‐time three‐dimensional transesophageal echocardiography (RT‐3D‐TEE). The main objective was to study the relationship between intraoperative annuloplasty ring size and mitral valve structure dimensions, with a focus on exploring the application value of RT‐3D‐TEE in MVP. Methods A total of 28 patients with degenerative mitral regurgitation (DMR), who underwent MVP between February and September 2022, as well as 12 normal control cases, were enrolled in this study. The MV annulus and leaflets were quantitatively analyzed using MVN software. Results The DMR group exhibited significantly greater dimensions in various parameters of the mitral valve, including the anterolateral‐to‐posteromedial diameter (DAlPm), anterior‐to‐posterior diameter (DAP), annulus height (HA), three‐dimensional annulus circumference (CA3D), two‐dimensional annulus area (AA2D), anterior leaflet area (Aant), posterior leaflet area (Apost), anterior leaflet length (Lant), posterior leaflet length (Lpost), and tenting volume (Vtent) compared to the control group. Conclusion Real‐time three‐dimensional transesophageal echocardiography provides valuable insights into the morphological structure of the mitral valve and lesion location. It can aid in surgical decision‐making, validate the success of MVP, and potentially reduce mortality and complications associated with mitral valve repair procedures. Objective: Investigate the structure of mitral valve in patients who have had mitral valvuloplasty (MVP) using real‐time three‐dimensional transesophageal echocardiography (RT‐3D‐TEE) to study the relationship between the use of intraoperative annuloplasty ring size and mitral valve structure dimensions so as to explore the application value of RT‐3D‐TEE in MVP. Methods: We enrolled a total of 28 patients with DMR, who underwent MVP in our hospital between February and September 2022 and 12 normal control cases, to conduct a quantitative study of the mitral annulus and leaflets using MVN software. Results: (1) The DMR group had greater DAlPm (anterolateral‐to‐posteromedial diameter), DAP (anterior‐to‐posterior diameter), HA (annulus height), CA3D (three‐dimensional annulus circumference), and AA2D (two‐dimensional annulus area) of the mitral valve compared to the control group with statistically significant differences (p < .05). (2) The DMR group had greater Aant (anterior leaflet area), Apost (posterior leaflet area), Lant (anterior leaflet length), Lpost (posterior leaflet length), and Vtent (tenting volume) of the mitral valve when compared to the control group with the statistically significant differences (p < .05). (3) There was a significant positive correlation between the mitral valve values of DAlPm, DAP, CA3D, AA2D, Aant, Lant, and DI (p < .05) and the annuloplasty ring size. (4) Using multiple linear regression, the DAP, Lant, and DI had a significant effect on the mitral valve annuloplasty ring size (R2 = .980, F = 387.375, p < .01), giving the linear regression equation: Y = 0.902 + 8.409X1 + 0.780X2 + 0.623X3. Conclusion: The morphological structure of the mitral valve and lesion location can be evaluated quantitatively using RT‐3D‐TEE to aid in surgical decision‐making. Measurements taken after operation can be used to validate the success of MVP, and reduce mortality and complications, increasing the value of this approach.