Cement slurry is commonly used with different additives in the oil well construction to fulfill many functions such as protecting steel casing from corrosion, restricting fluid movements between formations, isolating the drinking water zone et al.As one of the major additives, polymer latex is often added into the cement slurry to fulfill the tasks of enhancing the ductility and impermeability of hardened cement paste.Styrene-acrylate (SA) latex represents one of the main classes of polymer latex used in construction industry.However, a major drawback of the styrene-acrylate latexes is the severe retarding effect on the cement hydration, especially under elevated temperature.In order to disclose the retardation mechanism, a series of styrene-acrylic polymer latexes with varied monomer combination were syntheized through semi-batch emulsion polymerization.Butyl acrylate (BA) and styrene (St) are used as the major monomers during the synthesis.The mass fraction of BA in the total monomer amount varied from 0 to 62%.Influences of the synthesized latexes on the setting time of cement paste and the kinetics of cement hydration were investigated at 25 ℃ and 80 ℃ by means of Vica tests and isothermal calorimetry.