Objective:To research the mRNA expressions of Stat3 and Bcl-2 in process of malignant change of oral premalignant lesions. Methods:The mRNA expressions of Stat3 and Bcl-2 were detected in normal oral mucosa,simple hyperplasia epithelia,dysplasia epithelia and oral squamous cell carcinoma (OSCC) by RT-PCR. Results:The positive rate of Stat3 and Bcl-2 and the semiquantitative value(Stat3/GAPDH,Bcl-2/GAPDH) increased stepwise from normal mucosa,hyperplasia epithelia,dysplasia epithelia to OSCC. The expression of Stat3 was linear positively correlated to that of Bcl-2. Conclusion:There is some relation among Stat3,Bcl-2 and the process of malignant change of oral premalignant lesions.