Left hilar space occupation may be localized hilar lymph node enlargement, may also be early lung tumor space, if there is diabetes, coronary artery disease, hypertension, cardiovascular disease patients, aortic arch enlargement, space occupation is mostly cardiovascular imaging performance. If the pulmonary thromboembolism can be performed pulmonary arteriography, showing the presence or absence of thrombus, resulting in the left hilar occupation, the left hilar occupation is mostly malignant lesions, if necessary, can do chest enhancement CT, chest MRI and other tests to clarify the occupation of the tissue whether the enhancement or uneven enhancement, and to further determine whether it is a benign or malignant nodule. Left hilar occupations need to do fiberoptic bronchoscopy, mediastinal thoracoscopy and other tests, as soon as possible to take pathological tissue to determine its benign or malignant, left hilar occupations belong to the results of imaging tests, need to be combined with the chest CT and pathological tissues to clarify the cause of the disease. Patients with left hilar occupancy need to be diagnosed under the guidance of a physician and treated according to the physician’s recommendations.