Blends of polybutadiene (BR) and styrene-butadiene-styrene triblock co-polymer (SBS) have been prepared by a two-roll mill. The morphologies of extruded samples from a capillary rheometer were observed by scanning electron microscopy (SEM). It is found that PS phase is dispersed in the BR phase. The glass transition temperature (T-g) of the blend has been examined by using differential scanning calorimetry (DSC). From the T-g behavior and the electron microscopy study, it is found that certain degree of miscibility between the polystyrene phase and the BR phase is observed. The rheological behavior of the blend has been investigated by a capillary rheometer. It is found that the viscosity of the blend increases with increased content of PS phase. The behavior is in accord with the expected behavior of filler effect. To predict the filler effect of PS phase on the BR-SBS blend, a modified model of Chen and Cheng is proposed to elucidate the rheological properties of the BR-SBS blends with different compositions. Chen and Cheng＇s micromechanical model derived in Part I of this series, which relates the macroscopic shear stress to the macroscopic shear rate of a rigid non-Newtonian suspension when the direct contribution of Brownian force is completely neglected. The agreement between the theoretical predictions and the experimental results is satisfactory.