To investigate microtubule associated protein tau_related diseases,many studies have employed various cultured cell lines to study the aberrant tau modification.However,the cultured cells lack the natural extracellular matrix,neuronal connectivity and the normal neuronal expression of proteins. The use of cultured brain slices has become an accepted technique for theex vivo tool,yet the viability of this preparation is not routinely measured.The effect of temperature on the cell viability and the expression of tau was investigated in hippocampi slice culture of rat brain of different ages. Hippocampal slices of male Wister rats of 1, 2, 4 and 8 week-old were cultured at 34℃ and 37℃ for 3 weeks, respectively. The lactate dehydrogenase (LDH) activity and Western blotting were measured to evaluate the cell viability and expression of tau protein. Results were followed as (1) Effect of temperature on the viability of brain slice: Data from LDH assay showed that the slices could maintain activity for longer time at 34℃ than at 37℃, and at the same culture temperature, no obvious difference was observed in groups with different age; (2) Effect of temperature on expression of tau: The expression of tau in 4 and 8 week-old rat brain slices was more stable at 34℃ than at 37℃. Tau expression was significantly decreased at 37℃ and this decrease was becoming more obvious with increase of the age of rats. No effect of temperature was observed in 1 and 2 week-old rats. The results indicate that temperature at 34℃ is more suitable than at 37℃ for the survival and stable expression of tau in adult brain slice culture. On other hand,use of culture temperature and animal ages as signifcant functional parameter of regional slice viability also provides an inexpensive and expeditious means to enhances the feasibility of this preparation for function studies.