Abstract: Objective To identify the clinical importance of ultrasonic indirect sign for cholangiocarcinoma.Methods A total of 72 patients were diagnosed with cholangiocarcinoma which was proved by CT, MRI and surgery from December 2001 to December 2007.The patients' liver, gallbladder, pancreas and spleen were also examined using routine ultrasound in fasting state to observe especially obstructed biliary ducts, dilatation of proximal ducts and indirect sign of secondary changes of relative organs.The data was recorded carefully and the ultrasound images were stored to be compared with clinical follow-up results.Results All the proximal ducts of the 72 cholangiocarcinoma patients were dilatated of which 64 of the patients were with serious dilatation, and 8 patients with mild and moderate dilations.The positive incidence of biliary ducts dilatation was 100% .The ultrasound images had shown indirect sign of stenosis, the degree and shape of obstructed biliary ducts, the degree of dilatation and sphere of proximal biliary ducts, transitional status between dilatation and stenosis of biliary ducts, etc.The accuracy to determine obstruction position and the consistency to prompt etiological diagnosis were 97.22% (70 /72) and 94.44% (68 /72) , respectively.Conclusion Ultrasonic indirect sign has important clinical value to identify the obstruction position and point out etiological diagnosis.