Objective  To investigate the relationship between the expression changes of synaptosomal-associated protein 25 (SNAP25) and the onset of amyotrophic lateral sclerosis (ALS), explore the neuroprotective effect of SNAP25 on ALS motor neurons, and provide potential therapeutic targets for ALS.  Methods  Differentially expressed genes in ALS transgenic mice were screened using public databases. Focusing on SNAP25, 36 pairs of hSOD1-G93A transgenic ALS mice and their wild-type (WT) littermates at different disease onset time points were selected as animal models. hSOD1-G93A mutant and hSOD1-WT NSC34 cells were generated as ALS cell models. Real-time PCR and Western blotting were used to verify differential expression in vivo and in vitro. Immunofluorescence assays were performed to detect the co-localization of SNAP25 with neuronal marker neuronal nuclei (NeuN) in mouse spinal cords. SNAP25 was overexpressed in hSOD1-G93A mutant NSC34 cells, and cell viability was measured using a cell viability assay kit. After neurite induction, changes in neurite growth were analyzed, along with the expression of neurite-related proteins βⅢ-tubulin and growth associated protein 43（GAP-43). Results  Analysis of public databases revealed that SNAP25 expression was significantly lower in the spinal cord of ALS transgenic mice compared to WT mice. Animal studies confirmed that, compared to WT mice, the levels of SNAP25 protein and mRNA in the spinal cord of ALS mice decreased; SNAP25 co-localized with NeuN in the mouse spinal cord, and the integrated optical density of SNAP25 in SNAP25-positive neurons in ALS mice decreased. In vitro experiments revealed that the expression levels of SNAP25 protein and mRNA in hSOD1-G93A mutant NSC34 cells were reduced, and overexpression of Snap25 improved cell viability and promoted neurite outgrowth. Conclusion  The down-regulation of SNAP25 expression is closely related to the pathological process of ALS. Overexpression of Snap25 enhances the viability of hSOD1-G93A mutant NSC34 cells, promotes neurite outgrowth, thereby exerting a neuroprotective effect.