Objective: To explore the safety of laparoscopic modified transcystic biliary drainage (modified C-tube technique) in the treatment of biliary stones and application of diagnosing biliary disease. Methods: A retrospective analysis was conducted on the clinical data of 68 cases of biliary stones successfully treated with laparoscopic modified C-tube technique from August 2021 to December 2023. The safety, effectiveness, and area of applications were analyzed. The reliability of the principle of the modified fixation method was verified by using an ex vivo gallbladder. Results: Three cases of ex vivo gallbladder demonstrated that the strength of the modified fixation method was reliable, and the sinus tract formed by suture after immediate extraction of the C tube could be dislocated and closed, resisting the bile outflow caused by the weight of the gallbladder. Among the 68 patients, 42 were difficult biliary stones, 6 were suspected common bile duct stones, and 5 were extrahepatic bile duct stones combined with intrahepatic bile duct stones. Among them, 48 cases underwent choledochoscopy assisted trans-choledochal approach for stone removal, and 10 cases underwent transcystic approach stone removal, Six patients underwent simply basket exploration and removal of stones through the cystic duct (5 patients had no residual stones on postoperative C-tube angiography, 1 patient had suspected residual stones, and the patient refused further examination and treatment for no symptom), and 4 patients only underwent biliary drainage through the cystic duct; two patients with retained stone passed after the use of topical nitrate drip infusion via C-tube, seven cases underwent endoscopic retrograde cholangiopancreatography(ERCP), stone removal with the assistance of a C-tube after laparoscopic surgery, and the results were uneventful. The mean surgical time was (131±44) min (76-279 min), the maximum daily drainage volume of the C-tube was (401±235) mL/d (10-1 150 mL/d), the hospital stay was (8.6±3.6) d (2-19 d), and the mean time of C-tube removal was (11±6.9) d (5-46 d). There were 14 overall complications, including 2 residual stones, and 12 C-tube related complications, comprising of 1 grade Ⅲa, 2 grade Ⅱ, and 9 grade Ⅰ. There were 9 cases of C-tube related adverse events that did not cause complications, including 3 of early detachment, 2 of displacement, and 4 of deep insertion. The median follow-up time after surgery was 21 (2-30) months, and 5 patients had recurrent stones. Among them, 4 patients had slow contrast outflow during cholangiogram, and 1 patient had obvious pancreaticobiliary reflux. 55 patients underwent C-tube amylase measurement, and 9 cases showed a significant increase in bile amylase (349-44 936 U/L), suggesting the presence of pancreaticobiliary reflux. Conclusion: Laparoscopic modified C-tube technique can be effectively used in the treatment of biliary stones, which is relatively safe and can be attempted in the diagnosis of biliary diseases.