Objective:To observe the expression of P70 S6 kinase(P70 S6K) in parotid acinic cell carcinoma. Methods:P70 S6K expression was examined by means of SP immunohistochemical technique and Western blot test in 30 cases of parotid acinic cell carcinoma. Results:Western blot revealed that P70 S6K expression in parotid acinic cell carcinoma was 58% higher than that in normal parotid tissue. Immunohistochemical assay showed that positive expression ratio of P70 S6K in parotid acinic cell carcinoma and in normal parotid tissue was 100.0% and 33.3%(P