Abstract: SanGen Decoction was made through water extract method, constituent adjustment, high temperature sterilization and other means using phragmites communis root, rhizoma imperatae root and dandelion root as raw material.The best extracting parameters for preparing the phragmites communis root was 94℃, 74min, the solid-liquid ratio of 1∶15.8g/mL.That for rhizoma imperatae root was 96℃, 58min, solid-liquid ratio of 1∶19.4g/mL.And that for dandelion root was 86℃, 65min, solid-liquid ratio of 1∶14.2g/mL.The option formula of SanGen Decoction was the phragmites communis root liquor of 40%, the rhizoma imperatae root liquor of 40%, the dandelion root liquor of 13%, the white granulate sugar of 7% and the citric acid 0.1%.This production was yellow, clear and transparent and scented the smell of phragmites communis root, rhizoma imperatae root and dandelion root.