Abstract:Crohn's disease is a chronic，progressive，and non-specific inflammation of the gastrointestinal tract. Despite a significant increase in available therapeutic agents in recent years，a considerable proportion of patients exhibit an inadequate response or experience a loss of response to existing treatments，leading to a state of refractory disease. Furthermore ，there is a lack of consensus on the understanding of difficult-to-treat Crohn ' s disease. The International Organization for the Study of Inflammatory Bowel Disease has defined difficult-to-treat inflammatory bowel disease，providing an important framework for clinical research and practice. This article systematically reviews the definition of difficult-to-treat Crohn's disease，associated risk factors，selection of therapeutic drugs，evolving treatment concepts，and future directions in treatment，aiming to provide a beneficial reference for the diagnosis and management of difficult-to-treat Crohn's disease.