Abstract: Three methods for preparing the important raw material of Acetazolamide-2- amino-5-mercapto-1,3,4-Thiodiazole are presented,two of them are new and the yields are good.These methods use triethylamine and pyridine as solvent and basic catalyst. Some improvements in Acetazolamide synthesis are also introduced,Thus the production of Acetazolamide in China is made more economical and convenient.