Lung nodules are not pneumonia, and they are fundamentally different. First, from the definition of the two are very different, lung nodules is a kind of change on the imaging, not a specific disease, refers to the presence of the lungs on the imaging of the diameter of less than 3cm round high-density foci. Pneumonia is a specific clinical disease, refers to the inflammation that occurs in the lung tissue, mostly acute inflammation. Second, from the nature of the lesion, lung nodules include benign lung nodules and malignant lung nodules. And pneumonia itself is a benign lesion, an infectious lesion. Third, from the etiological point of view, pulmonary nodules can be caused by a variety of reasons, both by infectious factors, can also be caused by non-infectious factors, but also some of its own lung lymph node tissue manifestation. Pneumonia mostly refers to infectious foci, mostly caused by pathogenic bacteria, such as bacteria, fungi, mycoplasma, chlamydia and so on. Fourth, from the imaging point of view, pulmonary nodules are mostly manifested as rounded high-density foci, and pneumonia is manifested as flaky or patchy high-density shadows.