Objective To analyze the role of tropomodulin 1 (Tmod1) in the regulation of body water. Methods Using mouse kidney primary inner medullary collecting duct (IMCD) cells for the study, the primary cells were transfected with adenovirus to overexpress/knock down Tmod1. Western blot and real-time fluorescent quantitative PCR were used to detect the changes in Tmod1 protein and RNA levels to verify adenovirus efficiency. Subsequently, the expression of cyclin-dependent kinase 1 after overexpression/knockdown of TMOD1 was detected by Western blot. Results After the overexpression of Tmod1, the level of CDK1 protein increased significantly, and decreased after knockdown of TMOD1, with statistical significance (P<0.05). Conclusion Tmod1 may participate in the process of body water mediation by influencing CDK1, but its mechanism remains to be further studied.