The melt viscosity of binary blend of polycarbonate (PC) and low-molecular-weight polystyrene (L-PS) was examined by the measurements using a capillary rheometer. It was found that the addition of L-PS significantly reduces the melt viscosity of PC. Moreover, this viscosity drop became obvious at high shear rate region. The morphology observation of the extruded strand indicates that shear-induced phase mixing is the origin of this viscosity drop. The addition of L-PS does not sacrifice the transparency of PC due to the matching of refractive index. Therefore, this method is applicable to enhance the procesability of PC especially for injection-molding.