Objective To investigate whether Humanin (HN) has an in vivo neuroprotective effect on experimental mice with Alzheimer′s disease (AD) and the possible mechanism. Methods AD models were established by intracerebral injection?of β-amyloid?protein (Aβ). A total of 60 healthy male mice were randomly divided into 3 groups: sham operated group (n = 15), Aβ model group (n = 15) and HN treatment group (n = 30). Changes in expression of OX-42 in hippocampal region were observed by the immunohistochemical method on 3,7,14 days after modeling. Nissl staining was performed to detect the pathological changes of the hippocampal region of different groups of animals. Results The number of OX-42 positive cells in hippocampal region was reduced in HN treatment group on 3,7,14 days (P＜0.05). Pathological changes of the hippocampal region were detected by Nissl staining in both Aβ model group and HN treatment group after surgery, but the inflammatory changes of HN treatment group were less than Aβ model group at each time point. Conclusion In vivo, HN can reduce the expression of OX-42 induced by the toxicity of Aβ25-35 which proved that HN has neuroprotective effect.