In　this　study,　a　viscosity-reducing　polycarboxylic　acid　superplasticizer　(VRPCE)　was　synthesized　using　methylallyl　polyoxyethylene　ether　(HPEG),　acrylic　acid　(AA),　and　maltodextrin　maleic　acid　monoester　(MDMA)　as　the　main　raw　materials.　The　influences　of　the　VRPCE　on　the　microscopic　properties　of　cement　paste　were　studied　by　gel　permeation　chromatography　(GPC),　total　organic　carbon　test　(TOC),　zeta　potential,　laser　particle　size　analysis,　XRD,　MIP,　TG,　and　SEM.　Finally,　the　effects　of　the　VRPCE　on　the　macroscopic　properties　of　cement　mortar　were　evaluated　through　flow　time,　slump　flow,　compressive　strength,　shrinkage,　and　creep.　The　results　showed　that　the　VRPCE　can　improve　the　hydration　degree　of　the　cement,　optimize　the　pore　structure,　increase　the　porosity,　improve　the　fluidity,　compressive　strength,　and　creep,　and　decrease　the　shrinkage　resistance　of　the　cement　mortar.