Objective To investigate the clinical value of ultrasound blood flow parameters combined with serum carbohydrate antigen 125 (CA125) and carcinoembryonic antigen (CEA) levels in differential diagnosis of benign and malignant breast nodules. Methods 90 patients with breast nodules who were treated in our hospital from July 2023 to July 2024 were selected as the study objects. All patients underwent Doppler ultrasonography and serum CA125 and CEA levels were detected. According to the results of pathological biopsy as the gold standard for the diagnosis of nodule properties, patients were divided into malignant nodule patients and benign nodule patients. The diagnostic results of ultrasonography and serum test list were compared with the combined application. The consistency between the examination results and the pathological biopsy results was analyzed. To analyze and compare the diagnostic efficiency of ultrasonography and serum checklist and combined application in the differentiation of benign and malignant breast nodules. Results Among 90 cases of breast nodules confirmed by biopsy, 34 cases were benign and 56 cases were malignant. Compared with benign nodules, the ultrasound blood flow parameters RI, PI, PSV and serum CA125 and CEA levels in malignant nodules were significantly decreased (P<0.05). Compared with ultrasonography and serum test, the consistency, sensitivity, specificity and accuracy of ultrasonography blood flow parameters combined with serum CA125 and CEA levels were significantly improved with pathological biopsy results (P<0.05). Conclusion Compared with ultrasonography or serum test sheet, ultrasound blood flow parameters combined with serum CA125 and CEA levels can distinguish benign and malignant nodules in patients with breast nodules.