Synergetic　energy-water-carbon　pathways　are　key　issues　to　be　tackled　under　carbon-neutral　target　and　high-quality　development　worldwide,　especially　in　ecologically　vulnerable　regions　(EVRs).　In　this　study,　to　explore　the　synergistic　pathways　in　an　EVR,　a　water-energy-carbon　assessment　(WECA)　model　was　built,　and　the　synergistic　effects　of　water-energy-carbon　were　comprehensively　and　quantitatively　analyzed　under　various　scenarios　of　regional　transition.　Shaanxi　Province　was　chosen　as　the　representative　EVR,　and　Lower　challenge　(LEC)　and　Greater　challenge　(GER)　scenarios　of　zero-carbon　transition　were　set　considering　the　technological　maturity　and　regional　energy　characteristics.　The　results　showed　that　there　were　limited　effects　under　the　zero-carbon　transition　of　the　entire　region　on　reducing　water　withdrawals　and　improving　the　water　quality.　In　the　LEC　scenario,　the　energy　demand　and　CO2　emissions　of　Shaanxi　in　2060　will　decrease　by　70.9%　and　99.4%,　respectively,　whereas　the　water　withdrawal　and　freshwater　aquatic　ecotoxicity　potential　(FAETP)　will　only　decrease　by　8.9%　and　1.6%,　respectively.　This　could　be　attributed　to　the　stronger　demand　for　electricity　in　the　energy　demand　sector　caused　by　industrial　transition　measures.　The　GER　scenario　showed　significant　growth　in　water　withdrawals　(16.0%)　and　FAETP　(36.0%)　because　of　additional　biomass　demand.　To　promote　the　synergetic　development　of　regional　transition,　EVRs　should　urgently　promote　zero-carbon　technologies　(especially　solar　and　wind　power　technologies)　between　2020　and　2060　and　dry　cooling　technology　for　power　generation　before　2030.　In　particular,　a　cautious　attitude　toward　the　biomass　energy　with　carbon　capture　and　storage　technology　in　EVRs　is　strongly　recommended.