In order to investigate the relation between Cyclin D₁ protein expression in multistage tissue of pathological changes during the nasopharyngeal carcinogenesis and nasopharyngeal carcinoma(NPC), the simple hyperplasia/ metaplasia, atypical hyperplasia/metaplasia in the nasopharyngeal paracarcinoma mucous epithelium and NPC were studied for Cyclin D₁ expression with immunohistochemical streptavidin-peroxidase (SP) method by tissue array techenique. The positive rates were 30.0%（3/10）,90.0%（18/20）and 62.9%（39/62）respectively,among which hightening “instantaneously” in the atypical hyperplasia/metaplasia appeared. It is shown high Cyclin D₁ expression may be an early incident in the course of nasopharyngeal carcinogenesis, and that atypical hyperplasia/metaplasia probably be an important “toll-gate”.