Abstract: The variation of water and energy contents in the Major Energy Reserves were studied in adult grass lizards (Takydromus septentrionalis) from March to September,2000,which collected month by month from Langyashan Mountain,Chuzhou,Anhui,Eastern China.Males and females differed in water contents of tail-free carcass and liver.There were significant monthly changes in water contents and energy contents of tail-free carcass,tail and liver in both males and females.Significant monthly changes in energy contents of fat bodies were also found in both sexes.Energy contents of tail-free carcass (including lean tail-free carcass),tail (including lean tail) were all higher in males than in females,but those of liver lower in males than in females.The results indicated that seasonal variation in the major energy reserves were correlated with the reproduction and winter hibernation.