To investigate the mechanism of PI3K signaling-mediated hepatoma cell growth, specific PI3K inhibitor LY294002 were used to treat hepatocellular carcinoma cell line (SMMC-7721). LY294002 could inhibit cell proliferation of SMMC-7721. RT-PCR and Western blotting results showed that inhibition of PI3K signaling increased the protein expression of p27, but not mRNA expression. The protein expression of p27 could be inhibited by transfecting p27 SiRNA plasmid in LY294002-treated cells. And the knock-down of p27 protein expression could partly block the cell growth-inhibition induced by LY294002. Chx treatment experiment revealed that LY294002 prolonged the half-life of p27 protein, which increased its stability. In LY294002-treated cells, not only the mRNA expression of Skp2 (which is a critical molecule mediating the degradation of p27 protein) were reduced, but also the half-life of Skp2 protein were shorten. However, the activity alteration of Akt (an important downstream effector of PI3K signaling) by transfecting Akt constitutively active mutant and Akt dominant negative plasmid, did not influence the expression of p27. Taken together, these findings indicated that PI3K signaling regulated cell growth through modulating the degradation of p27 protein via Skp2 in SMMC-7721, however which was Akt independent.