To analyze the dosage and its characteristic of Fangji in different era, in order to provide the basis for clinical use of Fangji.Methods:The most representative medical works of each dynasty were selected, and the data base of the usage and dosage of Fang Ji was established. Maximal dosage, minimal dosage, average dosage, most common dosage, upper limit value of common usage and lower limit value of common usage of Fangji were statistically analyzed.Results:The dosage of Fangji in Han and Tang dynasties was large and broad, then decreased sharply from the late Tang dynasty, because of the prevalent of pulvis. Till Ming dynasty, as the main preparation changed form revert to decoction again, the dosage rose gradually，but the rage of common dosage was still narrow.Conclusion:The average dosage of Fangji was changed obviously in different era, meanwhile, large dose and even overdose existed in every era, which were used to treat severe cases of rheumatism or hydroncus.