Abstract: Objective To sutdy the effects of mitogen activated protein kinase(MAPK)and phosphatidy linositol 3-kinase(PI3K)on the inhibition of human bladder cancer cell proliferation induced by sulforaphane(SFN). Methods Methyl thiazolyl tetrazolium(MTT)assay was used to detect T24 cell proliferation.The level of cyclooxygenase-2(COX-2) mRNA was determined by quantitative real-time PCR. Results SFN(5-20μmol/L)significantly suppressed the proliferation and the expression of COX-2 mRNA.Pretreatment with inhibitor SB202190 or LY294002,anti-proliferation of SFN on T24 cells was remarkably attenuated by the increase of cell viability.Inhibitor SB202190,but not LY294002,could thoroughly masked the level of COX-2 mRNA downregulated by SFN. Conclusion The results suggest that p38MAPK and PI3K signal pathway are involved in the inhibitory effect of SFN on T24 cells and p38MAPK plays a key role in the inhibition of COX-2 mRNA by SFN.