The invention relates to a three-channel biliary endoscope, which is a core medical device used in the operations of endoscopic minimally invasive lithotomy in protect gallbladder and removing polypus, comprising a biliary endoscope and an external sheath tube by the design of which two channel for inserting operation devices is added. The three-channel biliary endoscope has the advantages that: at most three operation devices can be used during the operation of removing stones in protect gallbladder and take polypus, thus, the application range of the operation is enlarged and the safety andconvenience of the operation is enhanced; the terminal length of the biliary endoscope is shortened, the diameter of the forefront part of the three-channel biliary endoscope is more precise than thediameter of the prior endoscope, thus, the operation of removing stones in protect gallbladder and taking polypus can be finished better and the quality of the operation is enhanced.