Aim　To　isolate　HeLa　cell　proliferation-inhibitory　active　fraction　from　Pegasus　laternarius　Cuvier　and　explore　its　potential　apoptosis-inducing　mechanism.　Methods　To　obtain　the　active　fraction,　the　ethanol　extract　of　Pegasus　laternarius　Cuvier　was　chromatographed　by　silica　gel　and　sephadex　LH-20　columns;　MTF　assay　was　used　to　evaluate　the　proliferation-inhibitory　ability　of　active　fraction　on　HeLa　cells;　AO/EB,　PT　an(1　Annexin　V-FITC/PI　fluorescent　staining　flow　cytometry　were　used　to　evaluate　its　apoptosis-inducing　ability;　the　possible　mechanism　was　investigated　by　analyzing　the　enzyme　activity　of　caspase-3　and　the　protein　expression　of　apoptosis-related　genes　in　tumor　cells.　Results　A　fraction　of　C　with　high　HeLa　proliferation-inhibitory　activity　was　isolated,　with　a　yield　of　0.　73　%e　and　an　IC50　of　36.　3　mg　.　L-1;　fraction　C　could　increase　the　proportion　of　cells　in　sub-G0/G1　phase,　phosphatidylserine　eversion　and　other　typical　cell　apoptosis　in　a　dose-dependent　manner;　fraction　C　could　down-regulate　the　expression　of　Bcl-2　and　increase　the　enzyme　of　caspase-3　in　HeLa　cells.　Conclusions　The　active　fraction　C22　from　Pegcisus　laternarius　Cuvier　can　inhibit　the　proliferation　of　HeLa　cells　by　inducing　apoptosis.　The　effect　of　inducing　apoptosis　may　he　conducted　through　mediating　the　mitochondrial　Bcl2/caspase　pathway.