The steady and dynamic rheological behaviors of the aqueous solutions of linear polyvinyl alcohol (PVA) and two types of branched PVA with different branched degree were investigated. The steady rheological results show that the apparent viscosity of PVA aqueous solution decreases with the increase of branched degree of PVA under the same conditions. And the rheological measurements also reveal that the aqueous solutions of branched PVA are nonNewton fluids with a shear thinning characteristic, and the shearthinning effect increases with the branched degree of PVA. Dynamic rheological results show that the complex viscosity and molecular chain relaxation time of PVA aqueous solution are sensitive to the branched degree. Increasing the branched degree leads to the decrease of complex viscosity and molecular chain relaxation time.