Choledochal stones are categorized into primary and secondary. Primary stones can be induced by biliary tract infections, biliary tract obstruction, etc.; the latter are secondary to gallbladder stones. Choledocholithiasis, or extrahepatic bile duct stones, has many causes. Primary choledochal stones are mostly brown bile pigment stones, which can be associated with biliary tract infections, biliary tract obstruction, bile duct segmental dilatation, and biliary tract foreign bodies. Biliary foreign bodies commonly include Ascaris lumbricoides remnants, eggs, and suture thread knots. Secondary stones are mainly formed when gallbladder stones enter the common bile duct and lodge in the common bile duct area. In rare cases, they can also be caused by intrahepatic bile duct stones falling into the common bile duct. It is advisable to seek medical attention for timely diagnosis and treatment of common bile duct stones.