In　the　synthesis　of　functional　polycarboxylate　superplasticizers　(PCEs),　ester　monomer　was　usually　used　as　small　monomer　or　macromonomer.　However,　there　were　few　studies　on　the　co-introduction　of　small　ester　monomer　and　ester　macromonomer　into　one　PCE　molecule　and　its　effects.　In　this　study,　it　was　found　an　interesting　behavior　of　competitive　hydrolysis　between　these　two　ester　monomers　in　diester　PCE,　which　performed　higher　fluidity　of　cement　paste,　greater　adsorption　amount　and　shorter　prolongation　of　the　induction　period　of　cement　hydration　due　to　the　competitive　hydrolysis.　Furthermore,　the　kinetics　of　hydrolysis　and　adsorption　of　the　diester　PCE　were　probed,　and　the　rate　order　was:　ester　macromonomer　＜　small　ester　monomer　＜　diester　monomers.　This　study　aims　to　innovatively　reveal　the　special　behavior　and　mechanism　of　competitive　hydrolysis　of　PCE　using　diester　monomers　in　cement-based　materials　and　to　provide　a　theoretical　basis　for　enriching　molecular　design　and　innovative　application　of　functional　PCEs.