Abstract: Composite latex particles of disproportionated-rosin (DPR) and polyacrylates were synthesized by miniemulsion polymerization. The influences of dosage of initiator, surfactant and DPR, and the type of initiator on polymerization were studied by monitoring the conversion of monomer and variation of particle size. It was found that polymerization rate was increased with the increased dosage of initiator or surfactant; Particle size of miniemulsion was kept relatively stable during polymerization when an initiator of lower solubility was used; An increase in dosage of DPR reduced polymerization rate, but showed no significant impact on the final monomer conversion. It was also demonstrated that rosin in hybrid polymer functioned as a plasticizer to reduce glass transition temperature, which resulted in the reduction of strength and increase of elongation of polymer films.