PSF is an important tumor suppressor protein in eukaryotic cells. In Hela cells, PSF gene is mutant and leads to transform of its function. In order to clarify the function of PSF mutant (muPSF) in Hela cells, muPSF was knocked down by designed siRNA. Through the cell growth, wound scratch assay and detecting alternative splicing (AS) of downstream genes by semiquantitative PCR. The results showed that RNAi of muPSF expression could down regulate migration and proliferation of Hela cells, and rescue of muPSF had its ability to enhance the migration and proliferation. The study confirmed that muPSF, in Hela cells, regulated the migration and proliferation by AS of downstream genes.