Which nodules in the lungs are the most dangerous are generally high-risk lung nodules that have the potential for malignancy. Generally, large size of lung nodules, sub-solid nodules, isolated nodules, and nodules with burrs are manifestations of high-risk nodules. 1. Size: the larger the size of the lung nodule, the higher the risk of malignancy, especially nodules over 8mm, need to be alert to the possibility of malignant nodules. 2. Density: generally sub-solid nodules, especially mixed ground glass nodules, the degree of malignant risk is relatively high. 3. Number of lung nodules: Generally, the malignant possibility of multiple lung nodules is relatively low, and the malignant degree of isolated lung nodules is relatively high. 4. Lung nodule morphology: such as lung nodules with burrs, lobulation, eccentric cavities, pleural pulling, etc., are also manifestations of high-risk nodules. Lung nodules need to be clearly identified as the cause of the disease and followed up regularly in the hospital to observe changes in the nodules.