This study aimed to investigate the effect of diatrizoate vaginal stump markers on the dose distribution of postoperative radiotherapy for cervical cancer. From July 2022 to July 2023, 12 patients who underwent radical postoperative radiotherapy for cervical cancer at Gansu Provincial Maternity and Child-Care Hospital, Gansu Provincial Central Hospital, and who had cotton balls with meglumine diatrizoate placed to mark the vaginal stump before positioning were enlisted. Volume modulated arc therapy was designed as Plan A and was used in the actual treatment plan. The relative electron density value of the vaginal stump area marked by meglumine diatrizoate was replaced by the relative electron density value of the normal vaginal wall, and Plan B was recalculated, keeping the planning optimization parameters unchanged. The evaluation indicators and dose distributions were compared between the two group. The results showed that the Homogeneity index（HI）was slightly worse in the Plan B group than the Plan A group (1.048 vs. 1.047) but the Conformance index (CI) (0.870 vs. 0.868) was better in the Plan B group. The average dose to the planned target volum (46.48 vs. 46.47) and the dose to the vaginal stump (47.14 vs. 46.45) were higher for Plan B than Plan A, and the minimum dose to the rectum (6.42 vs. 6.49) was lower for Plan B than Plan A. The effect of diatrizoate vaginal stump markers on dose distribution was negligible.