Epigenetic changes plays an essential role in the phenotypic changes and biological processes associated with aging. DNA methylation is one of important epigenetic control mechanism that has been shown to be aging-related gene silencing. Age-related DNA methylation changes have been called ‘epigenetic drift’, but the defining features of this phenomenon remains unclear. To further explore and characterize the relationship between DNA methylation level and age, we performed the targeted bisulfite sequencing analysis over the next year in blood samples of 17 years old African green monkey. We observed that within the identical individual, global CpG, CHG methylation level trend to increase over time. In addition, we identified 59 aging-associated differential methylated regions (DMRs) in gene expression regulated or CpG island regions. Aging-associated hypermethylation regions were enriched regarding metabolic or biosynthetic process gene ontology (GO) terms, whereas hypomethylated regions showed no enrichment. According to aging-related gene function in DMRs, we selected 17 candidate genes, and performed the validation experiments through long term follow-up. Here we report that aging-associated DNA methylation changes in African green monkey identical individual through long term follow-up. These finding are invaluable resource to better understanding of epigenetic drift. Furthermore abundance accumulation of global methylation analysis of long-term follow-up in identical individuals might contribute to our understanding about genetic mechanisms of age-related phenotypes and diseases.