Aqueous polyurethane dispersion(PUD) were prepared from the Poly (Propylene)glycol (PPG-2000), Isophorone diisocyanate(IPDI) and Dimethylol propionic acid(DMPA), followed by the neutralization of pendant COOH group with Triethyl amine(TEA). Two series of samples were prepared. One seires were the samples having the different degree of neutralization but same size of the PU dispersion. Another had the same degree of neutralization but different particle size of dispersion latex. In this paper we will discuss the effect of the degree of neutralization and the ratio NCO to OH in polyurethane dispersion on the grafting efficiency in polyurethane seeded emulsion polymerization.