Since the 1970s,the invention of Peroral Cholangioscopy makes it possible to get direct visualization of the biliary tract, which helps in the diagnose of indeterminate biliary stricture and treatment of difficult common bile duct stone. Peroral Cholangioscopy was first described as Mother-Baby Scope System, which demands two endoscopists and seems relatively cumbersome for performance. The occurrence of the Single-Operator Peroral Cholangioscopy system, such as the Ultraslim upper endoscope and The SpyGlass system, has made great advances in high-quality imaging and satisfied maneuverability for biopsy and lithotripsy. The clinical usage should be based on different characteristics of each Peroral Cholangioscope system to select the appropriate model.