This study is designed to observed CBD stones cases with high recurrence risks applying IDUS or not during ERCP. Patients with CBD stone high recurrence risks were enrolled in this study, and prospectively randomized into IUDS group and control group during lithotomy. Operation time, radiation time, hospitalization cost, retain of nasobiliary tube, deployment of stent were recorded. Symptoms and conditions after ERCP were also followed up including blood amylase, routine blood test, abdominal pain, post-ERCP pancreatitis, resection of gallbladder, recurrence of CBD stone and onset of cholangitis.