According to available clinical statistics, the chance of a 5mm ground glass nodule in the lungs being benign is over 90%. Whether a 5mm ground glass nodule is benign or not should be considered in light of its size, density, morphology, growth rate, smoking history and family history. 1. In general, the smaller the lesion, the greater the likelihood of it being benign, especially as most nodules under 5mm are benign; 2. Some studies have suggested that the higher the proportion of solid components in ground-glass nodules, the greater the likelihood of benignity; 3. Most benign nodules are round or round-like in shape, while malignant nodules can be of various shapes, such as mulberry-shaped or bloom-shaped; 4. Generally speaking, nodules that have not grown for more than 2 years are likely to be benign; 5. If there is a history of smoking or family history, it is necessary to consider whether the nodule is malignant. The above considerations can be used to determine the chances of a 5mm ground-glass nodule being benign. However, the final characterization of whether the nodule is benign or not depends on pathology.