Anaerobic digestion is an attractive option for stabilization and conversion of the organic wastes to its end products methane and carbon dioxide, A large number of microorganisms investigated so far catalyze the anaerobic digestion processes. Numerous environmental factors directly or indirectly inhibit and affect the survival and growth of microorganisms, and temperature is one of particular significance. This paper presented an investigation of the effect of temperature on the methane potential during anaerobic digestion. 8 mL fresh thermophilic inoculum were placed in a glass vial of 108 mL with 0.5 mL substrate(acetate and propionate) and 31.5 mL nutrient solution. The vials were incubated at 9 different treatment temperatures ranging from 25 to 65℃. After a two-week adaptation, 0.5 mL substrate and 0.5 mL vitamin were refilled for all treatment vials and the methane formation in the headspace of vials was analyzed by a Shimadzu GC-8A equipped with a flame ionization detector(FID). Results indicated that at low treatment temperature of 25 and 30℃ no difference in the methane formation capacity was found between acetate and propionate, whereas the methane formation of acetate was always higher than that of propionate at other treatment temperature vials, except the treatment vials of 37 and 50℃. When acetate was used as the substrate, the highest methane production capacities were found at 40 and 55℃ with values of 0.39 and 0.37 mL CH₄ h^-1, respectively. However, when propionate served as the substrate, the highest methane production capacities of 0.32 and 0.38 mL CH₄ h^-1 were found at 37 and 50℃, respectively. The difference between the optimum temperature in the two tests is highly due to the fact that the inoculum used in this study is not pure microbial culture, even thought they have already pre-adapted to the specific treatment temperature and nutrient conditions. In conclusion, changes in temperature are strongly to have a substantial influence on the methane production capacities during the anaerobic digestion process.