Abstract: Objectives To study the relat ion and significance among tumor suppressor gene p16 expression and cellu lar DNA content in lung cancer. Methods The expression of p 16p rotein was determined by immunohistochemicalm ethod. The cellular DNA content was assayed by imagine analysis system. Results In 82 patients examined, 51. 2% showed p16 positive staining and p16 expression levels in adenocarcinoma exhibited higher than those in squamous cell carcinom as and small cell carcionom as (P < 0. 05). There were significantly difference respectively of the expression levels of p16 between lymph node metastasis group and no lymph node metastasis group and in groups of different clinical stages (P < 0. 01). p 16 positive staining rate in diploid was higher than that in aneuploidy. Conclusion Gene p16 play an important role in carcinogensis and progression of lung cancer and that they also correlate with the biological behavior and prognosis of lung cancer.