Slope　stability　is　generally　analyzed　by　a　two-dimensional　(2D)　method,　ignoring　the　spatial　effect　(SE),　which　no　longer　meets　the　evaluation　accuracy　requirement.　This　problem　is　particularly　prominent　for　embankments　built　on　double　V-shaped　gullies　(E-DVSG),　which　is　a　typical　but　unique　topography　in　mountainous　areas.　Moreover,　the　technical　requirements　for　engineers　will　increase　sharply　if　a　three-dimensional　(3D)　slope　stability　calculation　method　is　adopted.　To　tackle　this　issue,　pragmatically,　a　dimension-reduced　slope　stability　analysis　method　(DR-SSAM)　considering　the　SE　of　the　E-DVSG　was　proposed　and　verified　by　a　case　study.　Specifically,　the　DR-SSAM　obtained　the　3D　safety　factor　of　the　E-DVSG　by　using　the　spatial　effect　curves　and　the　safety　factor　from　the　2D　model.　The　results　showed　that　this　method　was　rational　and　efficient　for　engineering　applications.　In　addition,　the　SE　generation　mechanism　and　condition,　along　with　the　influences　resulting　from　the　major　factors,　were　addressed　thoroughly.