Background:In qualitative diagnosis of bile duct stenosis,single diagnostic measure is difficult to make a correct diagnosis,to combine several diagnostic techniques may be helpful to make an accurate diagnosis.The aim of this study was to evaluate the value of intraductal ultrasonography (IDUS),endoscopic brush cytology and K-ras,P53 gene mutation in the early diagnosis of malignant biliary stricture.Methods:From February 2012 to February 2013,84 patients with suspected malignant biliary stricture were performed IDUS firstly,then endoscopic brush cytology and finally K-ras,P53 gene mutation detection,the sensitivity,specificity,positive predictive value,negative predictive value and accuracy of all above ways were evaluated and compared.Results:Of 84 patients,52 cases were ultimately diagnosed malignant biliary stenosis;of which,9 cases had no recurrence or metastasis to other organs after radical operation during the follow-up period.IDUS combined with brush cytology and K-ras + P53 gene mutation detection had obvious advantage in the sensitivity,accuracy and negative predictive value than any other joint detection and single detection (the advantage was more significant compared with IDUS + brush cytology or any single detection P ＜ 0.01).There were obvious statistical significance in the sensitivity and accuracy between IDUS + brush cytology + P53 or IDUS + brush cytology + K-ras and IDUS + brush cytology or IDUS (P ＜ 0.05).There was no statistical significance in the sensitivity,specificity,positive predictive value,negative predictive value and accuracy between IDUS + brush cytology + P53 and IDUS + brush cytology + K-ras (P ＞ 0.05).Conclusions:IDUS combined with brush cytology and K-ras,P53 gene mutation detection is better than the separate detection and contribute to the early diagnosis of malignant biliary stricture.Its more widespread use is recommended.