Allergen specific immunotherapy (AIT) is to identify the patient's allergen, give the patient repeated exposure to the allergen extract, and gradually increase the concentration and dose until the target maintenance dose is reached, so that the patient can develop tolerance to the allergen, which is the only treatment that can regulate the pathogenesis of allergic diseases and change its natural course. In recent years, domestic and foreign scholars have made great progress in the clinical practice and research field of AIT. This article reviewed the relevant progress of the mechanism, efficacy and drug administration of AIT.