〔Abstract〕 Objective To explore the effect of different concentrations of relaxin-2(RLN-2) on the proliferation and migration abilities of human immortalized keratinocytes(HaCaT cells). Methods HaCaT cells were cultured in media with different concentrations of RLN-2, and the cells were cultured in media without RLN-2 as the control group.The effect on cell proliferation was assessed by using the CCK-8 reagent, the cell migration ability was evaluated throughin vitrocell scratch assay, the cell cycle was examined by flow cytometry, and the expression levels of cell cycle proteins Cyclin B1 and Cyclin A2 were detected by Western blot. Results After being cultured for 24 hours under RLN-2 concentration ranging from 10～100 ng/ml, HaCaT cells showed progressively increased proliferation and migration capabilities compared to the control group, with elevated expression levels of cell cycle proteins Cyclin B1 and Cyclin A2 and an increased proportion of cells in S and G2/M phases, peaking at 100 ng/ml. However, HaCaT cells cultured with 200 ng/ml of RLN-2 exhibited reduced proliferation and migration capabilities, decreased expression levels of Cyclin B1 and Cyclin A2, and a lower proportion of cells in S and G2/M phases compared to the 100 ng/ml group. Conclusion RLN-2 can enhance the migration ability of HaCaT cells within an appropriate concentration range and may also promote cell proliferation by increasing the expression of related cell cycle proteins and the proportion of cells in S and G2/M phases.