Objective:To investigate the methods and effects  of applying choledochoscope in  drainage of retroperitoneal abscess.
Methods:Eighteen cases of retroperitoneal abscess, who underwent open surgical debridement and drainage or PCD but the drainage was ineffective,  were selected for use of choledochoscope to irrigate and debride the abscess repeatedly.
Results:All of the 18 patients had effective choledoscopic treatment; in 17 patients the abscess healed and drainage catheter was successfully removed; but in one patient, who developed pancreatic fistula, was cured by internal drainage operation performed 6 months later.
Conclusions:Use of choledochoscope as an adjunctive treatment after drainage operation of retroperitoneal abscess is simple, safe, and effective.