Objective: To assess the sealing effect of a Magnetic-Sealing Uterine Manipulator (MUM) in isolated uterus. Design: Non - intervention study. Setting: This study was conducted at the First Affiliated Hospital of Xi’an Jiaotong University from November 2019 to April 2021. Population: Patients with early-stage cervical cancer who underwent radical laparotomy hysterectomy. Methods: The MUM closure test (group 2) and the control test (right-angle forceps closure tests, group 1 and 3) were carried out in an isolated uterus. Main outcome measure: DNA ploidy analysis system was used to analyze the exfoliated cells. Statistical analysis was performed using Wilcoxon signed rank test to assess the sealing effect of MUM. Results: We identified 36 patients. None regional node metastasis was found in all cases and only one of their tumors was larger than 4.0 cm. The mean numbers of exfoliated tumor cells in groups 1, 2, and 3 were 1, 1, and 2, respectively. There was no significant difference in the number of exfoliated cells between group 1 and group 3 (p=0.476). We merged the results of group 1 and 3. Furthermore, there was significant difference between right-angle forceps closure tests and MUM closure test (p=0.022). Conclusion: The sealing effect for MUM was better than the right-angle forceps. The MUM can effectively seal the cervical cancer cells in the cup cover and avoid the dissemination of tumor cells.