Abstract: Abstract　Objective: To discuss the value of the frozen technique in diagnosing and treating lung cancer through retrospective analysis of 1,138 cases with frozen sections of lung tumor. Methods: The intra-operative frozen section and diagnostic results of these cancer cases were collected and sorted, and then were compared with relevant paraffin sections and diagnoses of other cases. The characteristics of the frozen section and common causes of misdiagnosis of lung tumor were summarized. Results: The rate of intra-operative diagnostic accuracy and the misdiagnosis rate was 96.2% ( 1094/1138 ) and 3.8% ( 44/1138 ) in the 1,138 cases, respectively. The three diseases that ranked the highest in misdiagnosis were inflammatory pseudotumor ( 31.8%), sclerosing hemangioma ( 18.1% ), and tuberculosis ( 13.6% ). Conclusion: Diagnosis by intra-operative frozen section is extremely significant in determining the nature of lung cancer. Correct diagnosis requires comprehensive clinical data and sufficient diseased tissue. A good, common onco-pathologic basis, rich experiences in diagnosis with frozen section, and comprehensive clinical and diagnostic imaging knowledge of pathologists are necessary to ensure the reliability of diagnosis of cancer.