Dendrobium officinale, a traditional edible and medicinal plant, possesses significant medicinal and nutritional value. Specifically, the neuroprotective effect of Dendrobium officinale polysaccharide (DOP) has been increasingly recognized. However, the precise mechanism through which DOP exerts its neuroprotective effects remains incompletely elucidated. Accordingly, the present study integrated pharmacodynamics, serum metabolomics, lipidomics and hippocampal proteomics analyses to investigate the therapeutic effects of DOP and elucidate its underlying mechanisms in AD mice. Results showed that DOP significantly ameliorated cognitive impairment and hippocampal pathological damage in AD mice. Metabolomic and proteomic analyses revealed that DOP effectively reversed 43 differential metabolites (polar metabolites and lipids) and 137 different proteins. Joint analysis combined with Western blot validation suggested that the GnRH signaling pathway may function as a predominant neuroprotective mechanism associated with DOP. Collectively, this study provides novel evidence for DOP as a potential drug candidate for treating AD.