Whether a lung nodule 20mmx11mm is serious or not needs to be determined after the type of nodule is clarified, benign nodules are usually not serious and malignant nodules are more serious. Lung nodules can be classified into different types such as infected nodules or tumor nodules. Generally speaking, lung nodules larger than 8 mm on imaging are relatively more likely to be suspected of being malignant, but the exact type needs to be clarified after a pathologic biopsy is performed. Benign nodules such as infected nodules and tuberculous nodules are relatively less serious and can be relieved with anti-infective treatment, regular observation and follow-up, and surgery if necessary; malignant nodules are relatively more serious and can be treated with surgery, chemotherapy, radiotherapy, and other treatments. Therefore, it is recommended to consult a doctor as soon as possible for a clear diagnosis and standardized diagnosis and treatment of lung nodules.