Abstract: Objective 　To study the expression of DSB repair protein ( including Ku80, DNA-PKcs and ATM) in cervical carcinoma and cervical intra-epithelial neoplasia (CIN), and to explore their roles in neoplasia and tumor progression of cervical carcinoma. Methods 　Immunohistochemistry was used to detect the expressions of Ku80, DNA-PKcs, and ATM in 41 cases of cervical carcinoma and 15 cases of CIN. Results 　The positive percentages of Ku80, DNA-PKcs and ATM were 70. 7 %, 68. 3 % and 19. 5 % respectively in cervical carcinoma, and were 80. 0 %, 73. 3 % and 33. 3 % respectively in CIN ; the expression of three proteins in CIN were all higher than that in cervical carcinoma, but the differences has no statistical significance ( P > 0. 05) . The expression of these proteins was not associated with the age of patients, pathology, differentiation, and clinical stage ( P > 0. 05) . In all 56 cases, Ku80 was positively correlated with DNA2PKcs ( r = 0. 583, P = 0. 000) and ATM ( r = 0. 274, P = 0. 041) . Conclusion 　Three proteins might not play the major role in the neoplasia and tumor progression of cervical carcinoma ; Ku80 had closely relationship with DNA2PKcs and ATM in cervical carcinoma and CIN.