Based on literature research and data statistics，this article described the change of clinical dosage of Ma Huang (Herbal Ephedrae) from Han dynasty to present period.It showed that Ma Huang’s dose was Large before Song dynasty，and began to decline significantly from Jin and Yuan dynasty.This research had reviewed and checked the accurate dosage of Ma Huang(Herbal Ephedrae)，so as to broaden the thought of application of Ma Huang(Herbal Ephedrae).