Through the hydrosilylation the polydimethyl silicone surfactant(PSS) was prepared，and then styrene-acrylate emulsion was synthesized by semi-continuous pre-emulsified polymerization, and the PSS was used as emulsifier.IR analysis and EDS energy were used to tested the structure of PSS. The CMC was 4.53×10-6mol•L-1and the cloud point was 61~62°C.And then the effect of PSS dosage(wt%，1%~5%) on the properties of styrene-acrylate emulsion was studied. The results show that the more PSS was used, the conversion rate of monomer could be 98.65%, the gelation rate could be 0.87%, the stability of emulsion became higher firstly and then were stable, and the water absorption rate of the styrene-acrylate emulsion with the polydimethyl silicone as emulsifier was decreased to 9.51%, and defoaming times was 18s,has lower surface tension, shorter defoaming time, lower water absorption and better water resistance than the styrene-acrylate emulsion with emulsifier without polydimethyl silicone(Alkyl phenolic epoxy vinyl ether,OP-10).