Shrinkage-reducing　polycarboxylate　superplasticizer　(SRPC)　has　a　good　effect　on　reducing　shrinkage　of　cement-based　materials　because　of　its　low　surface　tension.　However,　the　effect　of　SRPC　on　the　properties　of　cement-based　materials　needs　to　be　further　explored.　A　comparative　study　of　SRPC　and　polycarboxylate　superplasticizer　(PCE)　was　carried　out　with　the　aim　of　correlating　the　adsorption　in　fresh　cement　pastes　with　their　dispersing　capability　and　the　impacts　on　cement　hydration.　The　results　indicate　that　the　adsorption　amounts　of　SRPC　are　less　than　PCE.　Both　of　them　exhibit　a　multilayer　adsorption;　the　fluidity　of　cement　pastes　with　SRPC　and　PCE　are　related　to　the　first　adsorbed　layer,　and　the　secondary　adsorbed　layer　does　not　contribute　to　the　enhancement　of　fluidity.　The　retarding　cement　hydration　of　SRPC　is　weaker　than　PCE　because　of　weak　adsorption　capacity　of　SRPC.