Objective:To observe and analyze the dynamic changes of hamster’s cheek pouch mucosa in different stages of the carcinogenesis under naked eye and light microscope with the carcinogenic agent dimethyl-benzanthracene(DMBA).Methods:DMBA was painted on hamster’s cheek pouch mucosa

3 times a week.Dynamic observation of the carcinogenesis of cheek pouch mucous membrane was carried out under naked eye;histological dynamic changes in the microstructure of cheek pouch mucosa in the carcinogenesis were observed under light microscope after the animals were killed respectively in the 2nd week

the 4th week

the 6th week

the 10th week

the 12th week and the 14th week.Results:For the cheek pouch mucosa of hamster painted with DMBA

the simple hyperplasia appeared in the 2nd week

the mild epithelial dysplasia in the 4th week

the moderate dysplasia in the 6th week

the severe dysplasia the partial changes of carcinoma in situ in the 8th week and cancer in the 10th week.All cancer models appearing in the experiment belonged to the well-differentiated squamous cell carcinoma.Conclusion:The carcinoma of hamster cheek pouch mucosa induced by DMBA is similar to the human oral squamous cell carcinoma so it is an ideal model for studying the oral squamous cell carcinoma in multi-stage and multi-step dynamic development.