If lung cancer is suspected after the appearance of lesions in the lung, firstly, pathology is taken to clarify, and two types of small cell and non-small cell must be distinguished, for non-small cell lung cancer try to distinguish squamous and non-squamous cancer, for non-squamous cancer, mainly adenocarcinoma, molecular testing must be performed, mainly checking two genes, EGFR and ALK. Next, PET and MRI are used to clarify the staging. Then individualized treatment is selected.