In this study, a pre-emulsified semi-continuous emulsion polymerization method was employed using styrene (St), butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), and N-hydroxymethyl acrylamide (NMA) as monomers to successfully synthesize styrene-acrylic microemulsions with small particle sizes and narrow distributions. The effects of two composite emulsifiers (SDS/AEO-9 and SR-10/AEO-9) on the properties of the emulsions were investigated under identical experimental conditions. The particle size and distribution, Zeta potential, chemical composition, water absorption rate, thermal stability, emulsifier migration, and surface morphology of the latex film were characterized by particle size analyzer, infrared spectroscopy, AFM, SEM, and TG. The results showed that when the emulsifier dosage was 6% of the total monomer amount, compared with the traditional SDS/AEO-9 emulsifier, the latex prepared with SR-10/AEO-9 emulsifier had a smaller particle size (63.75 nm), narrower distribution (PDI = 0.092), and Zeta potential absolute value > 50 mV. The water absorption rate of the latex film was lower than that of the latex film prepared with SDS/AEO-9, and the initial decomposition temperature of the latex film reached 367.2 ℃, indicating improved thermal stability. Additionally, AFM and SEM analyses showed that the latex film prepared with SR-10/AEO-9 had a dense film layer, with minimal emulsifier migration during film formation, meeting the requirements for decorative paper water-based ink binders.