The severity of cystic solid nodules in the left lobe of the thyroid gland is related to the nature of the nodule; if it is benign, it is usually not serious. If the nodule is malignant, it is more serious. A cystic solid nodule in the left lobe of the thyroid gland is the result of an imaging study, and since there is a difference between benign and malignant nodules, it is not possible to generalize whether a cystic solid nodule in the left lobe of the thyroid gland is serious or not. If a cystic solid nodule in the left lobe of the thyroid gland is benign, it is not serious and should be reviewed regularly. Malignant cystic solid nodules in the left lobe of the thyroid are more serious. Once the diagnosis is confirmed, timely treatment is needed. Surgical resection is the conventional treatment, which not only needs to remove the nodule, but also needs to remove part of the surrounding thyroid tissue, or even all of the thyroid gland. For patients who are found to have solid nodules in the left lobe capsule of the thyroid gland, further examination should be conducted to clarify the nature of the nodules, and the appropriate treatment should be chosen according to the individual’s situation.