Objective To investigate the effect of platycodin D on epithelial mesenchymal transformation (EMT) in human endometrial carcinoma Ishiwaka cell migration and invasion，and the regulation of transforming growth factor β (TGF-β) /Smad signaling pathway. Methods Ishiwaka cells in the fourth generation of logarithmically growing stage were randomly divided into control group，platycodin D group，agonist group and platycodin D+ agonist group. Cells in platycodin D group were added with platycodin D 18 μmol/L and cultured for 24 h. Cells in the agonist group were added with 20 ng/mL recombinant human TGF-β for 24 h，and cells in the platycodin D + agonist group were first added with 20 ng/mL recombinant human TGF-β for 24 h and then cultured with platycodin D for 24 h. Cell viability was detected by MTT assay，cell invasion ability was detected by transwell assay，cell migration ability was detected by scratch assay，and TGF-β1，p-Smad2/3，epithelial cadherin(E-cad) and neural cadherin (N-cad) were detected by western blotting. Results Compared with the control group，cell survival rate and relative expression levels of TGF-β1，p-Smad2/3，N-cad and cell migration and invasion ability in platycodin D group were decreased，and the relative expression level of E-cad protein was increased. The relative expression levels of TGF-β1，p-Smad2/3 and N-cad，cell migration and invasion ability in agonist group were increased，and the relative expression level of E-cad protein was decreased (P<0.05). Compared with the platycodin D group，the cell survival rate and the relative expression levels of TGF-β1，p-Smad2/3 and N-cad protein，the cell migration and invasion ability were increased in platycodin D + agonist group，and the relative expression level of E-cad protein was decreased (P<0.05). Compared with agonist group，cell survival rate and relative expression levels of TGF-β1，p-Smad2/3 and N-cad，cell migration and invasion ability in platycodin D + agonist group were decreased，and the relative expression level of E-cad was increased (P<0.05). Conclusion Platycodin D may regulate epithelial-mesenchymal transformation by inhibiting TGF-β1/ Smad2/3 signaling pathway and reduce the invasion and migration of human endometrial carcinoma Ishiwaka cells.