Multiple nodular lesions in the lungs can be caused by lung infections, pneumoconiosis, and tuberculosis with granulomatous type. 1. Lung infections: lung infections can cause multiple nodules in the lungs, such as pneumonia caused by Mycoplasma infection in the lungs, multiple nodular foci can appear in both lungs, and the patient will be accompanied by fatigue, low-grade fever and other symptoms. 2. Pneumoconiosis: Pneumoconiosis is an occupational disease, usually caused by inhaling too much dust. The accumulation of dust in the lungs will cause multiple nodules in the lungs, and in severe cases, the lungs will become fibrotic. 3. Tuberculosis of the corniform type: the appearance of multiple nodules in the lungs may also be due to acute tuberculosis of the corniform type. The patient will have low fever, fatigue, loss of appetite and other symptoms. There are other reasons for the sudden appearance of multiple nodules in the lungs, such as lung tumors, etc., which should be examined in the hospital in time for a clear diagnosis and early treatment.