This article aims to explain the concept of expelling phlegm method through collecting the terms related to expelling phlegm method in the ancient and modern literatures. It concluded that expelling phlegm method was the treatment which applied the method of digestion, guidance, vomiting, purging and nourishing to remove phlegm in internal organs, channels, limbs, skin, and fascia and so on. The expelling phlegm method could be categorized into four types: firstly, the digestion- guidance type, such as transforming phlegm, dispersing phlegm, and abducting phlegm, etc.; secondly, the vomiting type such as vomiting phlegm, eject phlegm and arising phlegm, etc.; thirdly, the purging type, such as precipitating phlegm, expelling phlegm, down bearing phlegm, etc.; fourthly, the nourishing type, such as moving phlegm. This article annotated these concepts from its source, meaning, application, formula and drugs.