〔Abstract〕 Objective To establish an in vitro cell model of Cobalt dichloride(CoCl2)-induced epithelial-mesenchymal transition(EMT) in rat renal tubular epithelial cells(NRK-52E). Methods NRK-52E cells were cultured in vitro and randomly divided into a blank control group(NC group) and a CoCl2 treatment group. The CoCl2 treatment group underwent 1, 2, 3, and 4 cycles of treatment, with each cycle consisting of CoCl2 treatment for 9 h followed by recovery in CoCl_2-free medium for 3 h. The optimal concentration and time of CoCl_2-induced EMT were screened using the CCK-8 assay. Morphological changes in cells were observed using light microscopy and phalloidin staining. The expression levels of EMT marker proteins were detected by Western blot and immunofluorescence. Results Compared with the NC group, stimulation by 100 μmol/L CoCl2 for 48 h significantly induced apoptosis(P2 for 9 h followed by recovery for 3 h(P2 for 9 h followed by recovery for 3 h, demonstrating the best model stability. Immunofluorescence results showed that compared with the NC group, the fluorescence intensity of the fibrous matrix protein Collagen I significantly increased in the 3-cycle group treated with 100 μmol/L CoCl2 for 9 h followed by recovery for 3 h(P2 for 9 h, following 3 h of recovery in CoCl_2-free medium. Repeating this cycle three times can establish an in vitro EMT model.