Highly crosslinked micron-size monodispersed PMMA/PDVB and PS/PDVB particles were prepared using seeded multi-stage emulsion polymerization. PMMA and PS seed particles were synthesized by seeded multi-stage emulsion polymerization and soap-free emulsion polymerization. Then PMMA/PDVB and PS/PDVB particles were obtained using semi-batch type emulsion polymerized using divinyl benzene as a cross-linkable monomer in the presence of seed particles. PMMA particles with size of ca. 730 nm and polydispersity of 1.03 were successfully prepared in this experiment. PS particles with size of ca. 1.5 ${mu}m$ and polydispersity of 1.01 were prepared in this experiment. Highly crosslinked PS/PDVB particles with size of ca. 1.3 ${mu}m$ and polydispersity of 1.00 were obtained.