If the single nodule at the angle of the left rib diaphragm is a calcified foci, it can be treated without special treatment; however, if it is tuberculosis or lung cancer, it should be treated in time. 1. Lung calcification foci: due to previous inflammation, resulting in local scarring, generally no special treatment, regular observation can be. 2. Tuberculosis: it is related to the infection of tuberculosis bacillus, and should be treated with anti-tuberculosis treatment, such as oral isoniazid, rifampicin, etc., so as to avoid delaying the condition. 3. Lung cancer: belongs to malignant tumor of lung, once diagnosed, it should be treated in time, or else the condition will be delayed, leading to the continuous spread of cancer cells. For early stage lung cancer, radical lung cancer surgery is feasible, and after the surgery, it will be decided whether radiotherapy is needed according to the individual’s condition. The single nodule at the angle of the left rib diaphragm does not clarify the nature of the nodule, so it needs to be diagnosed and analyzed by enhanced CT and pathological biopsy, and formal treatment should be carried out after knowing the nature of the nodule.