Abstract: Objective To investigate the clinicopathological features of anaplastic lymphoma kinase（ALK）protein positive expression in nonsmall cell lung cancer（NSCLC）patients. Methods The expression of ALK protein was detected in 141 cases of NSCLC by immunohistochemistry（IHC）. The data of clinicopathological features of patients with ALK positive expression was collected and analyzed. Results The positive rate of ALK protein in NSCLC was 9.2％（13／141）.The positive rate was closely associated with age and epidermal growth factor receptor（EGFR） mutation（P＜0.05），but not correlated with sex，smoking，drinking，histopathology，primary site，lymph node metastasis and the expression of thyroid transcription factor-1（P＞0.05）. Conclusion Young age（≤57 years），EGFR negative patients with NSCLC are recommended the detection of ALK.