The patency rate of biliary stents is typically 14% to 80% and is associated with cholestasis, granulation tissue proliferation in the stent lumen, and tumor growth into the stent. The patency rate decreases continuously with time. Biliary stent drainage can effectively relieve patients with malignant biliary obstruction, and endoscopic placement of a biliary stent is the optimal method of choice for patients with malignant biliary obstruction that cannot be radically resected surgically, with minimal trauma and few complications. However, the main complications of this method are postoperative cholangitis and stent blockage, which are the main factors limiting its clinical application. According to the literature, the patency rate of biliary stents tends to decrease with time, generally up to 14% to 80%, and the patency rate is related to cholestasis, granulation tissue proliferation in the stent lumen and tumor growth into the stent.