Abstract: This paper deals with the analysis of 110 cases atelectasis of cancer were diagnosed by x-ray, and the diagnosis of 104 cases had been comfimed by bronchofiberscopical examination and histopathology. The results showed the rate of diagnosis was correctly achieved in 94. 5% ;In all patiens，58 (55.8% ) cases were squamous cell carcinoma，25 (24% ) undiferentiated carcinoma， 12 (12 % ) adenocarcinoma，S (5% )unclassify I and 4 (3. 8% )unclassify I 6 (5. 5 % )cases non-cancer atelectasis 1 cases tuberculous and 5 cases inflammatory atelectasis. The characteris-tics and the portion of atelectasis in x-ray were conform to general rule;the findings of brocnch-nofiberscopy was asociated with different types histopathology. Therefore,author suggest that the patients of atelectasis of cancer who had been diagnosed by x-ray should be examinated by bron-chofiberscopy and biopsy，so as to be clear about the diagnosis of atelectosis in cancer or no.