As a few children had adverse reactions after BCG vaccination, some families irrationally had some unnecessary disputes with some departments of vaccination, and even some experts of tuberculosis also did unobjective explanation work and misled the patients, I will first introduce the necessity of BCG vaccination. BCG vaccine is a live bovine Mycobacterium tuberculosis vaccine named BCG, which is artificially attenuated but can produce specific cellular immunity. After more than 100 years of vaccination history, it has been confirmed that BCG is one of the safe vaccines and plays a great role in preventing the occurrence of childhood TB and reducing childhood TB deaths in countries or regions with high risk of TB infection. However, there is a misconception that if you get BCG vaccination, you will not get TB, which is wrong. BCG vaccination only reduces the severity of tuberculosis, but does not completely prevent the development of tuberculosis. BCG vaccination requires strict implementation of operational regulations by vaccinators, but before vaccination, it should be determined whether the child has an immunodeficiency disease, or has a suppressed immune response due to a malignant disease, or uses glucocorticoids, which are prohibited. Vaccination is also temporarily contraindicated if there are developmental malformations or disease infections in the process. After BCG vaccination, swelling of lymph nodes at the vaccination site (usually in the armpit) may occur, usually not more than 1 cm in diameter, and will subside in about 1-2 months. This is a normal reaction after vaccination. If the local lymph nodes form abscesses with fluctuations or break down after vaccination, local treatment or even anti-tuberculosis treatment is required. Disseminated BCG disease occurs in a very small number of patients after vaccination and is due to BCG vaccine spread infection. Most of these children have immune defects, such as congenital thymus deficiency or dysplasia, and a few have normal immune function. The left axillary or subclavian lymph nodes are enlarged 1-3 months after BCG vaccination, and in severe cases, they may break down and heal slowly. The disease usually starts in the peripheral lymph nodes and can involve the whole lymphatic system, and from the lymphatic system, it gradually involves the internal organs, with the liver, spleen and lungs being the most common. If the disease occurs after vaccination, it requires prompt treatment and has a high mortality rate. Therefore, it is important to understand BCG vaccination correctly and not to refuse vaccination because of side effects, but side effects should be treated correctly, especially in case of disseminated BCG disease, which should be treated actively, otherwise the consequences are serious.