Cavitation often occurs in lung squamous carcinoma, lung adenocarcinoma often appears as small peripheral nodular lesions, lung adenocarcinoma is prone to early distant metastasis, lung squamous carcinoma mainly occurs in the large upper lobe bronchus and appears as central lung cancer often accompanied by cavitation, lung squamous carcinoma is often common in middle-aged men who smoke for a long time. Whether it is lung cancer or not can be clarified only by fiberoptic bronchoscopy, or by aspiration pathology to find cancer cells. The cavity of lung cancer shows thick-walled cavity, eccentric cavity, irregular and unsmooth inner edge of cavity wall, while the cavity of tuberculosis shows thin-walled cavity, fungus can also show cavity change, but the wall of cavity caused by infectious lesion is thin, and the cavity will dissipate and absorb rapidly after anti-infection treatment.