Multiple nodules are more dangerous if they are formed by metastasis of malignant tumors, while single nodules are more dangerous if they are irregular in shape, burr-like, and infiltrate and grow to the periphery. Therefore, the degree of danger cannot be evaluated according to the number of nodules, and CT, MRI and other imaging examinations combined with puncture biopsy are needed to determine the nature and severity of the nodules. The analysis is as follows: 1. Danger of multiple nodules: when single nodules in the lungs are caused by inflammation or benign tumors, they can be cured after drug or surgical treatment in general. However, when multiple nodules are caused by primary lung cancer cells invading surrounding tissues in many places, or caused by distant metastasis, and patients have clinical symptoms such as chest pain, hemoptysis, dyspnea, etc., then multiple nodules are more dangerous. 2. Danger of single nodule: if chest CT, chest X-ray and other imaging examinations find that single nodule in lung is irregular in shape, burr-like, and infiltrates and grows to the surrounding, destroying blood vessels and tissues, presenting the behavior of malignant tumor, and biopsy and puncture confirms the diagnosis of malignant tumor, single nodule is more dangerous at this time. Therefore, to determine the danger of nodules can not be based on single or multiple, need to be combined with CT, MRI and other imaging tests combined with puncture biopsy in order to determine whether the nodules are dangerous or not. It is recommended that patients complete the relevant examinations as soon as possible to clarify the nature of the nodules and then treat them as soon as possible. Do not delay treatment.