In this article, the particle morphology in emulsion polymerization of the poly(vinyl acetate) (PVAc)/poly(butyl acrylate) (PBA) system is investigated. With the use of the basic data in literature, the relevant interface tensions and viscosity are estimated with the equation proposed in literature. The time achieved to equilibrium morphology is predicted with cluster dynamics proposed by Gonzalez. The experiment result is consistent with that of prediction.