Objective To investigate the effect of 5-Aza-CdR on Notch1 pathway and neural regeneration and to explore the effects of 5-Aza-CdR on learning memory ability in mice by exploring active avoidance behavior.Methods Sixty 6～8-week-old SPF-grade ICR male mice were divided into two groups.5-Aza-CdR was administered to one group of mice via lateral ventricular injection,while the control group was injected with bovine serum albumin.Notch1 and HES1 mRNA and protein expression levels were detected by Real-time PCR and Western blot 24 hours after injection;5-bromo-2'-deoxyuridine-positive cells were observed by laser confocal microscopy,and Notch1 expression in hippocampal dentate gyrus was viewed with laser confocal microscopy.Notch1 methylation changes were detected by ethylation-specific PCR,and learning and memory behaviors of mice were assessed by passive avoidance tests and shuttle avoidance assays.Results Injection of 5-Aza-CdR increased hippocampal Notch1 pathway activity,promoted neuronal regeneration in the DG region,decreased methylation levels in the Notch1 promoter region,and enhanced the ability of mice to perform active avoidance behavior.Conclusions The effect of 5-Aza-CdR on active avoidance behavior may be related to the influence of hippocampal neural regeneration through the Notch 1 pathway.