To explore the diagnostic value of endoscopic retrograde cholangiopancreatography (ERCP) combined with modified biopsy forceps for suspected malignant biliary obstruction, 72 patients with suspected malignant biliary obstruction who underwent ERCP using modified biopsy forceps from January 2017 to April 2023 in the First Affiliated Hospital of Henan University of Chinese Medicine were selected as the modified group, while 61 contemporaneous patients who underwent ERCP with traditional biopsy forceps were selected as the control group at the same time. The stenosis site was identified during the operation, and the effective pathological tissue was obtained by biopsy. Benign or malignant tumor was determined according to the medical history and clinical follow‑up data. The sensitivity and specificity of the two groups were compared. The success rate of biopsy was 100.00% in the two groups. All patients had no serious complications and were diagnosed histologically. Sixty‑seven cases were finally diagnosed as malignant and 5 cases were benign in the modified group. In the control group, 58 cases were malignant and 3 cases were benign. The sensitivity for diagnosis of malignant biliary stricture was 79.10% (54/67) in the modified group, and 60.34% (35/58) in the control group, with significant difference (χ2=6.218, P= 0.013). The specificity of the two methods for the diagnosis of malignant stenosis was 100.00%. Therefore, it is safe and effective to apply ERCP combined with the modified biopsy forceps in the diagnosis of extrahepatic malignant bile duct stenosis.