Abstract: Objective To explore the influence of norcantharidin on biological behavior of T24 bladder urothelial carcinoma(T24) cells.Methods The inhibition of norcantharidin of different dosages on the proliferation of T24 cells was detected with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT).The apoptosis of T24 cells was assessed with Hoechst33342 staining.The inhibition of non cantharidin on the invasion of T24 cells was determined with transwell assay.The expressions of matrix metalloproteinases-2 (MMP-2) and vascular endothelial growth factor(VEGF) were measured with enzyme-linked immunosorbent assay (ELISA).Results Different dosages of norcantharidin could inhibit the growth of T24 cells significantly,with a dose-effect relation (P<0.05).The apoptosis rate (16.02±0.75% and 28.28±1.17%) of T24 cells exposed to 4 and 16 μmol/L norcantharidin increased significantly but the number of invasion of T24 cells (23.33±1.53 and 16.17±2.47) decreased significantly compared to those of the control group (all P<0.05).The expression levels of MMP-2 (5.04±1.02 and 3.02±1.15) and VEGF (0.65±0.09 and 0.48±0.11)were down-regulated in the T24 cells exposed to 4 and 16 μmol/L norcantharidin (all P<0.05).Conclusion The proliferation and invasion of T24 cells can be inhibited by norcantharidin and norcantharidin could inhibit expressions of MMP-2 and VEGF in T24 cells.