Abstract: Objective To observe the effect of oxaliplatin on expression of drug resistant gene in DNA damage repair in human colon cancer cells.Methods The human colon cancer cell line HCT116 was processed with oxaliplatin for 48 hours.Western blot was used to examine DNA damage induced by oxaliplatin treatment.CCK-8 assay was used to explore the effect of oxaliplatin on growth of HCT116.The real-time PCR was used to detect the expression of DNA repair genes after oxaliplatin treatment.Results After the treatment of oxaliplatin,the expression of the DNA-damage-marker gene γ-H2AX increased significantly,and DNA damage excision repair related gene XPC increased significantly as well.The mRNA expression of other DNA damage repair genes had no significant increase.Conclusion The gene XPC might play a key role in generating drug resistance when treating colon cancer with oxaliplatin in clinic.