The morphological evolution of the latex particles obtained by VAc／BA two stage emulsion polymerization was studied．The designs of two group experiments were as follows：VAc as seed

BA was added in starved or overflown condition．The inverted core-shell composite latex particles

with PVAc as shell and PBA as core

were found in overflown condition

however

the core-shell composite latex particles

with PVAc as core and PBA as shell were found in starved condition．When the core-shell composite latex particles in different time in starved condition was kept to reaction end

the morphology of the latex particles inverted．Comparing with the previous work in literature

this paper can provide better and more complete understanding about the morphological evolution of the latex particles in the process of seeded emulsion polymerization of VAc／BA．The photos of TEM of morphology of the latex particles in the process under two conditions and temperature being kept constant were obtained．From viscosity

the existed paradoxical views about the morphology of the latex particles on VAc／BA can be explained in a better and more complete way．