Although breast cancer screening has been conducted for more than 40 years, there are still divergent views on the pros and cons of this work. Supporters believe that breast cancer screening can detect the lesion at an early stage and can be cured with a simple surgery; while opponents believe that not all cancers detected by screening can save their lives, and all screening methods have certain false positives and false negatives: those with false positives suffer from false alarms, and those with false negatives are more likely to mislead patients, resulting in delayed diagnosis and treatment, with even worse consequences. Breast cancer is one of the most suitable cancers for screening Currently, the World Health Organization recommends only two types of cancers for screening, cervical cancer and breast cancer, because these two types of cancers develop slowly, just like the gentle character of women, and there is enough time to detect them clinically before they infiltrate or metastasize. There is a consensus in Western countries that the application of regular radiographs and surgical examinations can indeed reduce the mortality rate of breast cancer by about 30%. Nowadays, the Western world has adopted such screening once a year or every other year for women over 40 years of age as a major means of breast cancer prevention, and has achieved remarkable results. The age of onset of breast cancer in Chinese women is 10-15 years earlier than that in the West, but fortunately, the development is slower and even if it develops naturally, the treatment effect is better, so the age of starting screening for the first time should be advanced to 35 years old and continue until 70 years old. From the experience of Europe and the United States, breast cancer screening has four main benefits for women: firstly, the cure rate of stage I cancer among breast cancers detected by screening is over 90%, which can significantly improve the cure rate; secondly, early breast cancer can be treated with less destructive breast-conserving surgery, so it can not only be cured but also maintain a good quality of life. Thirdly, since the treatment is simpler, the economic burden and pain caused by expensive chemotherapy drugs can be avoided; finally, all family tragedies that may result from late stage of breast cancer can be prevented, and even the social problems caused by it can be avoided. Since breast cancer screening is to detect pre-clinical asymptomatic cancer, it requires two necessary conditions: firstly, the screening method must be highly sensitive, so that cancer can be detected at a very early stage, preferably before it infiltrates or metastasizes; secondly, the specificity of the detection method means that a healthy person cannot be suspected as a cancer patient, as screening is often done from initial screening to precise screening. Since screening is often done step by step and sequentially, just like sieving with sieves of different sizes, there will be some false positives in the initial screening, but this false positive must be guaranteed not to be too high, otherwise it will affect the efficiency of screening, which requires women to go to the designated breast screening unit for screening.