Currently, breast cancer is the most common malignant tumor in women and is increasing year by year, but its mortality rate is decreasing, which is attributed to the early diagnosis and systematic and individualized treatment of breast cancer. Breast self-examination and clinical breast examination (BSE) is a method for women to perform breast palpation regularly to improve the early detection of breast cancer, but the sensitivity of BSE is only 20%-30%. Clinical breast examination (CBE) is a visual and palpable examination of the breast by a trained physician in asymptomatic women, with a sensitivity of 58.8% and a specificity of 93.4%. There is still a lack of clinical trials evaluating CBE alone for the early diagnosis of breast cancer. The American Cancer Society guidelines still recommend CBE as a measure for early diagnosis of breast cancer in asymptomatic women over 40 years of age. Mammography (MG) is the most commonly used method for the early diagnosis of breast cancer. A number of randomized clinical trials have demonstrated that its use in early breast cancer screening can reduce breast cancer mortality, and the advent of digital MG can further improve the accuracy of diagnosis. However, MG has poor visualization of dense breast lesions and has a high rate of missed diagnoses; Mandelson et al. showed that the sensitivity of MG was as high as 80% in fatty glands, but only 30% in dense glands. Breast ultrasound (BUS) is simple, non-invasive and economical. With the application of high frequency ultrasound probes, the resolution of ultrasound has been further improved. Currently, BUS has become an important screening method for early diagnosis of breast cancer, especially for women with dense glands, and an important complementary screening tool for MG. In recent years, automated whole breast ultrasound (AWBU) has been introduced to solve these problems, and with the help of a computer system, it can store information about the whole breast and help analyze the lesions. MRI has a high spatial and temporal resolution of soft tissues and is not affected by the denseness of the breast gland, so it can show breast lesions more clearly. In addition, MRI is more sensitive to multicentric and multifocal lesions. However, MRI is expensive and is generally recommended only for screening of women at high risk of breast cancer, such as those with a significant family history of breast cancer and breast cancer susceptibility gene (BRCA1/BRCA2) carriers, as an adjunct to mammography and ultrasonography. In the early diagnosis of breast cancer in China, the diagnosis of bloody nipple discharge is an important issue. According to our data, 9% of bloody nipple discharge is caused by ductal carcinoma in situ (DCIS), while 52% of DCIS manifests as bloody nipple discharge, and more importantly, 50% of DCIS patients with blood in the nipple as the main manifestation have no cancerous signs such as malignant calcified foci or masses. FDS is a miniature endoscope that can directly observe breast ductal lesions and perform intra-ductal biopsy and cytological examination, which are important for the diagnosis, treatment and localization of breast ductal lesions. Pathologic diagnosis is still the gold standard for breast cancer diagnosis. Currently, the pathological diagnosis of breast cancer includes fine-needle aspiration cytology (FNAC), core needle biopsy (CNB), vacuum-assisted biopsy (VAB) and traditional surgical biopsy. FNAC has the advantages of being simple, safe, and economical, but does not provide a histologic diagnosis, whereas most authors believe that FNAC can be used as a definitive diagnosis of breast cancer in cases where the clinical presentation, imaging, and FNAC are suggestive of malignancy, despite the lack of histopathologic evidence. For non-palpable breast lesions, imaging-guided aspiration biopsy or localized open surgical biopsy is the gold standard for the pathologic diagnosis of these subclinical breast lesions, with a 1.1% missed lesion rate and a 1.0% false-negative rate for malignant lesions as reported in the literature. Currently, the VAB technique has been widely used in clinical practice. Compared with general puncture biopsy, the success rate and accuracy of VAB biopsy are higher, close to traditional open surgical biopsy, but less invasive than traditional surgical biopsy, with less obvious postoperative scarring and better cosmetic results.