Purpose To explore the accuracy of ALK fused gene expression by immunohistochemistry ( IHC) in non-small cell lung cancer ( NSCLC) patients, and to investigate the clinical and pathological features of ALK-positive NSCLC patients. Methods By u-sing rabbit monoclonal D5F3 antibody, ALK IHC was performed on 234 NSCLC patients. ALK positive cases were confirmed by reverse transcription-polymerase chain reaction ( RT-PCR) . Results The positive incidence of ALK by IHC in 234 NSCLC specimens was 8. 97% (21/234), the positive rate of ALK fused gene verificated by RT-PCR was 5. 98% (14/234). There was significant difference with histological type, age, stage (P<0. 05), but no significant difference with gender, smoking history, tumor differentiation. Of 21 cases of ALK-positive NSCLC patients, the consistency of IHC and RT-PCR was 0 when IHC was ( +) , however, when IHC was or immunohistochemical score was >120, the consistency rate was 100%. Conclusion Although immunohistochemical expres-sion of ALK fused gene may have a certain false positive, IHC or immunohistochemical score> 120 show very high value for ALK fused gene RT-PCR followed by ALK immunohistochemistry in lung cancer is a economical and feasible method for the valuation of ALK fused gene.