Abstract: Objective To study the different roles of knocked – down c-Jun amino-terminal kinase 1 (JNK1) and c-Jun aminoterminal kinase 2 (JNK2) in expression of Hacat cells. Methods JNK1 and JNK2 siRNA were transfected into Hacat cells. The expression level of Hacat cells was measured by Western blot. The proliferation of Hacat cells was detected by CCK-8 assay. The cell cycle of Hacat cells was assayed by flow cytometry. The apoptosis of Hacat cells was induced by different doses of Taxol.Different expressions of normal and JNK1/2 knocked-down Hacat cells were analyzed. Results The knocked-down JNK1 and JNK2, especially JNK1, could reduce the proliferation of Hacat cells. The knocked-down JNK1 could decrease the number of Hacat cells at S phase and increase the number of Hacat cells at G2/M phase. The apoptosis of Hacat cells increased significantly in knocked-down JNK2.However, no significant difference was found in normal and JNK1 knocked-down Hacat cells. Conclusion The effect of JNK1 is better than that of JNK2 on proliferation of Hacat cells, whereas the effect of JNK2 is stronger than that of JNK1 on apoptosis of Hacat cells.