Abstract： Objective： To investigate the molecular mechanism of carnosol regulating the proliferation and invasion of bladder cancer T24 cells. Methods：Bladder cancer T24 cells were respectively divided into the T24 cell group，the 5-fluorouracil group and the carnosol groups with low and high dose(the low-dose group and the high-dose group). The 5- fluorouracil group was given 50.0 μg/mL of 5- fluorouracil， and the low- dose and high- dose groups were given 50.0 μg/mL and 100.0 μg/mL of carnosol respectively. All groups were cultured for 72 hours. Cell proliferation， the number of colony formation as well as the levels of invasion and migration， apoptosis， peroxisome proliferator activated receptor γ(PPARγ)，β-catenin mRNA and protein in each group were measured. Results：Compared with those in the T24 cell group，the apoptosis rates and the levels of PPARγ mRNA and protein expressions in the other groups were increased(P＜ 0.05)；the OD value，survival rate，the number of cell clone formation and cell membrane penetration，and the levels of β- catenin mRNA and protein expressions were decreased(P＜0.05). Compared with those in the 5- fluorouracil group，the apoptosis rate and the levels of PPARγ mRNA and protein expressions in the low-dose group were decreased(P＜0.05)，and the OD value，survival rate，the numbers of cell clone formation and cell membrane penetration，and the levels of β-catenin mRNA and protein expressions were increased(P＜0.05)； the apoptosis rate and the levels of PPARγ mRNA and protein expressions in the high- dose group were increased(P＜0.05)， and the OD value， survival rate， the number of cell clone formation and cell membrane penetration，and the levels of β- catenin mRNA and protein expressions were decreased(P＜ 0.05). Compared with those in the low- dose group， the apoptosis rate and the levels of PPARγ mRNA and protein expressions in the high- dose group were increased(P＜0.05)， and the OD value， survival rate， the number of cell clone formation and cell membrane penetration，and the levels of β- catenin mRNA and protein expressions were decreased(P＜ 0.05). Conclusion： Carnosol can inhibit proliferation， invasion and migration of bladder cancer T24 cells and promote their apoptosis. Its mechanism may be related to the promotion of PPAR mRNA and protein expressions， activation of PPARγ signal pathway by carnosol，and therefore inhibit β-catenin mRNA and protein expressions.