Abstract: Emulsifier is an important ingredient in emulsion polymerization, and will give some influence on the performance of the synthesized emulsion. Synthesis and application of SAE surface sizing agent was taken as the sample to examine the influence of emulsifier on the synthesis and application of SAE. Styrene, acrylic ester and acrylic were used as the monomers, acid sodium laurel sulfate (SDS) and alkylphenol ethoxylates (OP-10) as emulsifier, FeSO4H2O2  as initiator system, and appropriate amount of starch was added in. Orthogonal design was utilized to compare the effect of four factors on the synthesis and application of SAE surface sizing agent, such as the dosage and proportion of emulsifier, the starch amount and the revolving speed in preemulsification stage. The most suitable additive amount of synthetic sizing agent was also discussed in this paper. The results showed that the amount of emulsifier had the most influence on the property of product. The optimum conditions were as follows: amount of emulsifier 2 % to monomers, revolving speed 600 r/min, amount of starch 20 % to monomers, SDS scale 1 % to total emulsifier. Taking this sizing agent, Cobb value of paper decreased to 39.2 g/m2. When the additive was 5 % to the dry weight of starch, compared to no addition, Cobb value decreased by 58.4 % and the surface strength enhanced by 57.7 %.