The plasmid pXJ-41-p15, which contains the full length DNA coding for p15 was introduced into human melanoma cell line A375 in which p15 was deleted by DNA recombination and transfection. Using G418, the positive clones were selected. And the cell model overexpressing p15 was constructed successfully through the analysis of PCR and Western blot. It is showed that the expression of p15 was further enhanced after the cells overexpressing p15 were treated with PMA for 72 hours. In contrast of the control cells, the PKC activity was further declined in the cells overexpressing p15 after treated with PMA. At the same time, the growth rate of cell was decreased more significantly and approximate 30% apoptotic cells were found. The expression of Caspase-3(P20) was increased in the apoptotic cells. It is indicated that CKI p15 was related to PKC signal transduction in the regulation of cell proliferation and apoptosis. They may be involved in the apoptotic pathway including Caspase3, thus inducing the apoptosis of cells.