OBJECTIVE To study the mechanism of curcumol inhibiting the pro liferation of breast cancer cells T 47D. METHODS MTT assay was used to detect the inhibitory effects of different doses of curcumol （0，6.25，12.5，25，50，100 μg/mL）on the proliferation of T 47D cells. After treated with curcumol （12.5，25，50，100 μg/mL），the morphology of T 47D cells was observed by inverted phase contrast microscope. The cell cycle and the levels of reactive oxygen species （ROS）were detected by flow cytometry. Quantitative real-time PCR （qRT-PCR）was used to detect the expressions of proliferating cell nuclear antigen （PCNA），cell cycle regular p 21 and cyclin-dependent kinase 2（CDK2）mRNA. Western blot assay was used to detect the protein expression of CDK 2，CDK6，Cyclin D ，PCNA，nucler transcription factor E 2-related factor （Nrf2）and Kelch-like ECH associated protein 1（Keap1）. Breast cancer cells T 47D were divided into 2 groups，one group was given different doses of curcumol ，and another group was given curcumol 33 μg/mL for 6，12，24，48 h. After the optimal oxidation time and administration concentration were determined according to the results of the above two groups ，the blank control group ，N-acetylcysteine（NAC）group（ROS antioxidant NAC alone ），curcumol group （curcumol alone ），curcumol combined with NAC group （pretreatment with ROS antioxidant NAC ，and then adding into curcumol ）. Cell cycle and fluorescence intensity of ROS were detected. RESULTS Curcumol could significantly increase the inhibitory rate of the proliferation of T 47D cells （P＜0.05 or P＜0.01），and showed a certain dose and time dependent trend. Curcumol blocked the ， cycle in the G 1 phase and significantly increased the level of ROS （P＜0.05 or P＜0.01）；ROS antioxidant NAC could significantly reverse above inductive effect of curcumol （P＜ 0.01）. qRT-PCR showed that curcumol down-regulated the com expression of PCNA and CDK 2 mRNA and up-regulated the expression of p 21 mRNA（P＜0.05 or P＜0.01）. Western blot assay showed that curcumol significantly down-regulated the edu.cn protein expression of Keap 1，Nrf2，CDK2，CDK6 and Cyclin D（P＜0.05，P＜0.01）；ROS antioxidant NAC could reverse the down-regulation effects of curcumol on the expression of these proteins（P＜0.05 or P＜0.01）. CONCLUSIONS Curcumol may induce oxidative stress and cell arrest in G 1 phase to inhibit the proliferation of T 47D cells.