Abstract:Eosinophilic chronic rhinosinusitis(ECRS) is an inflammatory disease of respiratory mucosa, which is characterized by eosinophil infiltration. Eosinophil is a special type of inflammatory cell, which is closely related to Th2 type immune response.There are four main mechanisms that promote and maintain eosinophilic inflammation in ECRS patients:the biological effects of interleukin-5 (IL-5) in regulating eosinophils, immunomodulatory effects of eosinophilic extracellular traps, autophagy regulation and abnormal fibrin deposition. ECRS is characterized by complex etiology, difficult cure and easy recurrence.Eosinophils play an important role in the occurrence and development of ECRS.This article reviews the latest reports at home and abroad in order to provide theoretical basis for the treatment of ECRS.