Abstract: Yigong powder is one of the classic famous prescriptions published in the Catalogue of Ancient Classical Famous Prescriptions (the Second Batch of Pediatrics). Through systematically collating textual research and analyzing ancient literatures and clinical literatures on Yigong decoction, the key issues of prescription origin, composition, drug base, processing method, usage and dosage, efficacy and indications of Yigong powder were summarized, providing literature data support for the development and clinical application of the classic pediatric prescription of Yigong powder. According to the analysis and research, Yigong powder comes from Qian Yi's Key to Diagnosis and Treatment of Children's Diseases and is consisted of ginseng, poria cocos, atractylodes, tangerine peel and licorice, with ginger and jujube being used as guiding medicine. The medicinal base follows the 2020 edition of Chinese Pharmacopoeia. Ginseng, poria cocos, and orange peel are used as raw products, atractylodes is used as bran fried atractylodes, licorice is used as processed licorice. Children should be differentiated from adults in terms of drug dosage. The dosage for children is 1.4— 1.7 g each for ginseng, poria cocos, atractylodes, tangerine peel and licorice, and the dosage for adults is 5.6 g— 6.8 g each. The method of making and taking medicine is to file drugs down, take 300 mL water, add ginger and jujube and fry to 210 mL, take warm medicine before meals and adjust the frequency according to the actual situation. The ancient prescription was often used in children anorexia, diarrhea and other diseases. After the innovation of later generations of doctors, it is also used for digestive system diseases, recurrent respiratory tract infections in children, allergic rhinitis and so on.