〔Abstract〕 Qihai acupoint is the most commonly used point in clinical acupoint for the treatment, mainly treating all diseases caused by qi mechanism. There are many records about Qihai acupoint in the book of "Compendium of Acupuncture and Moxibustion". The author summarizes and sorts out the relevant records in the book, in order to provide some theoretical basis for the modern clinical application of this point. Qihai acupoint is renmai acupoint and the sea of vitality. It is located 1.5 inches below the umbilicus and on the midline of the abdomen. It has a wide range of treatment. It can treat qi machine diseases, gynecological and obstetric diseases, urogenital diseases, abdominal diseases, mental diseases, edema, hematemesis, dysentery and other diseases. It can be used alone or in combination with other acupoints. It is necessary to grasp the nature of acupoints and select acupoints according to syndrome differentiation.