Carbonation　curing　of　precast　concrete　components　can　address　their　low　production　efficiency　and　high　carbon　dioxide　emissions.　The　effect　of　mechanical　property　enhancement　and　carbon　dioxide　absorption　capacity　of　precast　concrete　components　during　carbonation　curing　is　determined　by　the　reaction　degree　of　the　cement,　and　achieving　the　desired　reaction　degree　requires　that　the　hydration　and　the　carbonation　reaction　durations　are　coordinated.　Herein,　the　effects　of　different　hydration-carbonation　processes　on　mechanical　properties,　the　relationship　between　the　degree　of　the　hydration-carbonation　reaction　and　mechanical　properties,　and　the　mechanism　that　affects　the　degree　of　the　hydration-carbonation　reaction　were　investigated.　Results　showed　that　the　optimal　hydration-carbonation　reaction　within　the　age　of　1　d　was　8　h　of　hydration　combined　with　16　h　of　carbonation.　The　compressive　strength　of　the　cement　mortar　by　this　reaction　process　was　approximately　20　MPa　higher　than　that　of　the　24　h　hydration.　Carbonation　at　the　hydration　stage　near　before　reaching　the　peak　hydration　heat　flow　facilitates　Ca2+　leaching　from　calcium　silicate　minerals,　increasing　the　reaction　degree　of　the　cement　and　resulting　in　the　highest　mechanical　property　enhancement,　which　further　promotes　Ca2+　consumption　in　the　cement　pore　solution　and　continued　Ca2+　leaching　from　calcium　silicate　minerals.