AIM To study the influence of ginkgo biloba exocarp polysaccharides(GBEP) on p53 gene expression and telomerase activity of human gastriccancer SGC 7901 cells in vitro . METHODS The p53 gene expression level of human gastriccancer SGC 7901 cells were measured by immunohistochemistry ABC. The telomerase activity of human gastriccancer SGC 7901 cells were measured by TRAP ELISA. RESULTS GBEP(80~160 mg?L -1 ,48 h) inhibited the expression of mutated type p53 genes and telomerase activity of human gastriccancer SGC 7901 cells. CONCLUSION The action mechanism of GBEP that inhibited the proliferation of SGC 7901 cells may relate to its down regulation effect on the expression of p53 genes and telomerase activity of human gastriccancer SGC 7901 cells.