Objective: To analyze the clinicopathological and immunohistochemical results of CT guided percutaneous lung biopsy specimens, and to investigate the diagnostic value of serum tumor markers in the diagnosis of pulmonary space occupying lesions. Methods: The pathological diagnosis of 81 specimens of CT guided lung biopsy, of which 25 cases of immunohistochemical results and 73 cases of the concentrations of serum tumor markers [carcino-embryonic antigen (CEA), cytokeratin-19-fragment (CYFRA21-1), neuron-specific enolase (NSE)] were analyzed retrospectively. Results: The diagnosis rate of 81 specimens of CT guided percutaneous lung biopsy was 96.3%, there were 53 cases of malignant lesions included 29 adenocarcinoma, 20 squamous carcinoma, 1 small cell carcinoma, 1 uncertain type of non-small cell lung cancer, 1 other types of lung cancer and 1 thymic carcinoma. Twenty-two cases of benign lesions included 7 inflammatory mass, 5 tuberculosis, 7 pneumonia, 3 pneumoconiosis, 2 inflammatory pseudotumor and 1 neurilemmoma. Immunohistochemical staining was used in 25 cases, 24 cases were diagnosed as malignant lesions included 13 adenocarcinoma, 8 squamous carcinoma, 1 small cell carcinoma and 2 uncertain type of lung cancer. The positive rate of P63 and CK5/6 in squamous cell carcinoma were 87.5%, TTF-1 and CK-7 were 69.2% and 76.9% in adenocarcinoma, there were significant differences between them (P<0.05); the sensibility of CEA, CYFRA21-1, and NSE of diagnosis the lung cancer were 54.9%, 68.6%, and 37.3% respectively. In combined detection for three targets, the sensibility rate was 80.4%. Conclusion: Combination of pathological and immunohistochemical detection of CT-guided percutaneous lung biopsy specimen with lung tumor makers can improve the sensitivity and accuracy rate of diagnosis of early stage lung cancer. Immunohistochemical results are useful to identify the pathologic category of lung tumor.