Objective: To study the elimination half-life of propofol in mouse brain. Methods: One hundred and forty mice were injected with propofol 32 mg/kg through caudal vein. The mice were divided into 14 groups with different time points, i.e. 1,2,3,4,5,6,7,8,9,10,15,30,45,and 60 min,with 10 mice in each group. The mice were killed to obtain arterial blood by picking off their eyeballs, and their brains by cutting off their heads. The concentrations of propofol in serum and brain were measured by high performance liquid chromatography. The parameters of elimination half-life were calculated by software 3P97. Results: Time to peak concentration of propofol in serum was about 1 min, and time to peak concentration of propofol in brain was about 3 min. The elimination half-life of propofol in brain were (9.6? 0.5) mins. Conclusion: The peak concentrations of propofol in brain was later than it in serum. There is correlation between the concentrations of propofol in blood and in brain. The metabolism of propofol in effect site could be measured accurately by the elimination half-life in brain.