Concentrated suspensions of charged stabilized colloidal particles exhibit very large viscosity at low shear rate, a strong shear-thinning behavior at intermediate shear rate, and a constant second Newtonian viscosity at high shear rate. This type of non-Newtonian behavior is affected by many factors such as the particle volume fraction φ, the particle diameter, the surface electric potentialψ0,salt concentration, etc. The generalized equation for the viscosity η of this system is proposed by applying Eyring’s transition state theory. The surface electric potentialψ0and the thickness of the electric double layerκ−1are determined by applying the theory to experimental data. Systematic experiments of η of the model colloidal dispersion systems are carried out as the function of φ and shear rate and the results are satisfactorily reproduced by the present theory. The effects of hydrodynamic diameterdhandψ0of the colloidal particle on η are also quantitatively explained.