Significant　energy　transition　would　be　needed　in　China　under　the　carbon　neutrality　target.　Since　it　would　have　important　impacts　on　water　resource　through　increased　usage,　understanding　the　water　demand　under　specific　climate　change　targets　could　enable　better　policy-making　for　the　energy　transition.　In　order　to　quantitatively　analyze　the　impacts,　this　study　proposed　a　methodology　that　combines　CO2　emissions,　energy　transition,　and　water　demand.　An　energy-water　integrated　assessment　model　was　built,　to　simulate　the　future　energy　and　CO2　emissions　pathways　up　to　2050　in　China.　The　water　demand　of　energy　systems　under　both　policy　scenario　(PS)　and　two　mitigation　scenarios　(2C　and　1.5C)　are　calculated.　The　key　influencing　factors　of　water　demand　are　analysed　in　two　low-water-demand　mitigation　scenarios　(2C-LW　and　1.5C-LW).　The　results　showed　that　China＇s　future　energy　system　and　CO2　emissions　pathways　change　significantly　under　mitigation　scenarios.　The　timing　of　the　CO2　emissions　peak　advances　from　around　2030　under　the　PS　scenario　to　between　2020　and　2025　in　the　mitigation　scenarios.　Near-zero　emissions　are　achieved　by　2050　under　the　1.5C　scenario.　However,　with　no　further　water-saving　measures,　water　consumption　in　energy　sector　would　continue　to　increase　under　both　the　policy　scenario　and　mitigation　scenarios.　This　pressure　is　compounded　by　certain　mitigation　technologies,　such　as　inland　nuclear　power,　biomass　energy,　and　CCS　technologies.　As　such,　the　potential　for　water　conservation　in　energy　system　under　climate　mitigation　targets　is　studied.　The　results　showed　that　water-saving　measures　can　significantly　reduce　long-term　water　demand　in　the　energy　system.