To explore the molecular mechanism by which 28-hydroxy-3-oxoolean-12-en-29-oic acid inhibits the invasion and migration of SGC-7901 and BGC-823 gastric cancer cells, we used Western blotting to measure the protein levels of mmp-2, mmp-9 and timp-1 and found that the expression levels of mmp-9 in 28 hydroxy-3-oxoolean-12-en-29-oic acid-treated sgc-7901 and bgc-823 gastric cancer cells were decreased, while that of timp-1, the inhibitory factor of mmp-2 and mmp-9, was increased. This evidence concerns the gene MMP2 and gastric cancer.