Objective: To detect the changes of p16 and FHIT and investigate their relationship in esophageal squamous cell carcinoma development by measuring their expression levels in normal squamous epithelium tissue, mild, moderate, severe dysplasia lesions, carcinoma in situ and invasive squamous cell carcinomas. Methods: Expressions of p16 protein and FHIT protein were detected and analyzed in 17 cases of normal squamous epithelium, 16 cases of mild dysplasia, 16 cases of moderate dysplasia, 17 cases of severe dysplasia, 10 cases of carcinoma in situ, and 18 cases of esophageal squamous cell carcinoma by immunohistochemical method. Results: With increasing histopathologic grades, the expressions of p16 and FHIT became gradually lower. There was no remarkable difference of p16 and FHIT expressions between the normal and mild dysplasia group (P＞0.05), but the differences between the normal and other groups were all significant (P＜0.05). There was no remarkable difference among the squamous cell carcinoma group, the moderate and severe dysplasia groups, and the carcinoma in situ group (P＞0.05), but significant differences existed in the expressions of p16 and FHIT proteins between the squamous cell carcinoma and the normal groups, and between the squamous cell carcinoma and the mild dysplasia groups (P＜0.05). There was an association of descending trend between p16 and FHIT protein expressions. Conclusion: Reduced expressions of p16 and/or FHIT proteins possible play an important role in the early occurrence of esophageal cancer. There was a positive correlation between the expressions of p16 and FHIT proteins.