Objective To analyze the diagnostic value of ultrasound imaging in breast space occupying lesions. Methods A total of 328 patients with breast space occupying lesions who visited our hospital from June 2021 to May 2024 were selected for the study. All patients underwent ultrasound examination, and the pathological diagnosis results were used as the gold standard to analyze the diagnostic accuracy, sensitivity, specificity, and diagnostic characteristics of ultrasound imaging for different types of breast space occupying lesions. Results Among 328 cases of breast space occupying lesions, 28 cases were malignant and 300 cases were benign, including 28 cases of breast cancer, 80 cases of lobular hyperplasia, 165 cases of fibroadenoma, 45 cases of complex cyst of breast, and 10 cases of lipoma of breast. The ultrasound imaging diagnosis results showed 30 cases of malignancy, 298 cases of benign, 3 cases of misdiagnosis, and 1 case of missed diagnosis. The diagnostic sensitivity was 96.43% (27/28), the specificity was 99.00% (297/300), and the accuracy was 98.78% (324/328). The consistency test with pathological diagnosis showed a Kappa value of approximately 0.842, which is very consistent with the pathological diagnosis results. The proportion of malignant lesions with irregular morphology, uneven edges, uneven internal echoes, axillary lymphadenopathy, weakened posterior echoes, and aspect ratio ≥ 1 is higher than that of benign lesions (P<0.05). Conclusions Ultrasound is a non-invasive, convenient, and economical imaging examination method with high sensitivity, specificity, and high consistency with pathological diagnosis results in the diagnosis of breast space occupying lesions. It can not only provide rich morphological features, but also effectively distinguish malignant and benign lesions, and has important clinical application value.