The polymerization kinetics and the morphology of PVC-seeded styrene emulsion polymerization were investigated. Batch polymerization technique was employed find transmission electron microscopies coupled with O_SO₄, RuO₄-staining methods were used for the morphological studies. The rate of polymerization was found to be independent of the swelling time find the initiator concentration (K₂S₂O₈), but it increased along with the agitation speed. The strong acidic condition of polymerization medium and the addition of isoprene, DVB or CHBr₃ slowed down the rote of polymerization. The PVC-PS composite latexes had constant morphology regardless of the change in polymerization parameters. The "off-centered core-shell (PVC-core, PS-shell)" morphology was thought to be originated from the low swelling of PVC with styrene. Crosslinking agent mode the morphology "concentric core-shell" and a common solvent to PVC find PS made the smooth composite particles.