In-stent restenosis(ISR) is a significant cause of long-term prognosis after percutaneous coronary intervention (PCI). The inflammatory response is a critical factor in its development. Unlike the chronic inflammatory process of traditional atherosclerosis, ISR may develop acute coronary events within even months or years, and the inflammatory mechanisms of ISR are more complex. Inflammatory factors regulate various mechanisms, including monocyte macrophage proliferation, endothelial cell damage and repair, foam cell formation, and smooth muscle cell proliferation and migration after PCI. The review briefly describes the classification and risk factors of ISR. It emphasizes the role of various inflammatory factors in ISR to provide new ideas for investigating the inflammatory mechanism of ISR and clinical intervention.