A series of polyester-vinyl copolymer hybrid aqueous dispersions were prepared by in-situ polymerization of some vinyl monomers in the presence of hydrophilic polyester and by neutralizing with different amount of triethylamine (TEA). The rheologic properties for these hybrid aqueous dispersions were examined and studied. The experimental results show that the particle size decreases with increasing the neutralization degree, but viscosity increases. The approximate Newton fluid behaviors are observed for the hybrid aqueous dispersion at low neutralization degrees as well as at high temperatures.