Abstract: Abstract In this paper,data about 48 cases of pulmonary carcinoma with cavity formatien were analysis,in which 34 (70.8% ) were squamous carcinoma, 11 (22.9% ) were adenocarcinoma and 3 (6.3%)were undifferentiated small cell carcinoma. The cases were all diagnosed during fiberbronchoscopicexamination with cytologic and for pathologic evidence either through biopsy apd brush biopsy oreven bronchopulmonazy biopsy (TBLB). It is suggested that carcinomatous cavity appears morecommon among aged patients with squamons carcinoma. The significance of differential diagnosisbetween pulmonazy carcinoma with carity formation and other kinds of pulmonazy carernou, diseare was emphasized. formation and development of pulmonazy carcinomatous cavity were analysisand new concept presented.