Abstract: OBJECTIVE To study the pharmacokinetics of drug in rat's brain by establishing a model that can collect cerebrospinal fluid at different times. METHODS The rat's head was fixed by the antrum auris and cutting tooth after anesthesia using brain stereotaxis. Cut and open the skin in corona capitis to find the crossing line between the cranium and muscle in cervical part. The needle used to collect the cerebrospinal fluid pricked into the center point of the crossing line and was pushed down by the "Z" axis slowly. When the depth of 0.6-0.9 cm (the number of the depth depended on the body weight of the rat) was arrived, the cerebrospinal fluid would be got. RESULTS The achievement ratio of single collection was 100% based on the data of 26 rats and the achievement ratio of multiple collections (6 times and above) was 80% based on the data of 10 rats. CONCLUSION The model is proved to be simple, stable, high efficient and repeatable and is suitable to be adopted to apply in brain research in rats.