Calcium　sulfoaluminate　(CSA)　cements　have　lower　carbon　dioxide　(CO2)　emissions　during　production　compared　with　conventional　ordinary　Portland　cement　(OPC).　However,　the　high　cost　of　production　is　a　significant　limitation　of　the　application　of　CSA　cements.　This　paper　aims　to　improve　the　use　efficiency　of　CSA　clinker　by　adding　OPC　and　anhydrite.　The　low-carbon　OPC-CSA　clinker-anhydrite　system　is　expected　to　contain　less　CSA　clinker　while　showing　excellent　performance.　A　design　methodology　was　developed　to　optimize　the　component　of　the　OPC-CSA　clinker-anhydrite　blended　system.　The　hydration　mechanism　of　the　ternary　system　was　investigated　using　isothermal　conduction　calorimetry,　X-ray　diffraction　(XRD),　and　thermogravimetric　analysis　(TGA),　and　thermodynamic　modelling　was　used　to　predict　the　amount　of　hydration　products.　The　results　showed　that　ettringite　is　the　main　hydration　products　of　the　OPC-CSA　clinker-anhydrite　system,　and　the　addition　of　OPC　provides　portlandite　for　the　formation　of　ettringite.　The　ternary　system　is　characterized　by　rapid　development　of　strength　and　low　CO2　emissions.　The　compressive　strength　at　4　h　and　the　CO2　emissions　are　about　10　MPa　and　500　kg/t,　respectively.　In　addition,　the　ternary　system,　composed　of　27.9　wt%　CSA　clinker,　32.5　wt%　anhydrite,　and　39.6　wt%　OPC　has　the　highest　compressive　strength　at　28　d　and　the　lowest　CO2　intensity.　©　2023　Elsevier　Ltd