Abstract: Objective: To detect the gene expression of Ku 70, Ku 80, ERCC 4, lig 4 and DNA-PKcs in non-homologous end joining pathway in human primary glioma tissues and normal brain tissues and to explore the underlying mechanism. Methods:The expression levels of Ku 70, Ku 80, ERCC 4, lig 4 and DNA-PKcsin in 36glioma samples and12normal brain tissue samples were measured by SYBR Green real-time quantitative PCR. Methylation of DNA-PKcs was detected by methylation-specific PCR (MSP). Results: There was no significant difference in Ku70, Ku 80, ERCC 4 and lig4 expression between human primary glioma and normal brain tissues (P<0.05), while DNA-PKcs was significantly up-regulated (P=0.002 ). The expression of DNA-PKcs was significantly higher in grade Ⅲand Ⅳglioma than that in grade Ⅱglioma and normal brain tissues ( P<0.05). Moreover, glioma tissues showed weaker methylation than normal brain tissues. Conclusion: The up-regulation of DNA-PKcs may be associated with pathogenesis of glioma. Demethylation of DNA-PKcs promoter is an important reason for its up-regulated expression in glioma.