In most of polymer processings, such as injection molding and extrusion, materials are subjected to high deformations. In order to study nonlinear viscoelastic properties, it is necessary to have an instrument to generate high shear rates. A new sliding plate rheometer incorporating shear stress transducer has been developed. This rheometer has been equipped with a robust servohydraulic linear actuator which can generate shear rates and frequencies up to 900 (1/S) and 500 (Hz) respectively, compared with maximum 500 (1/S) and 100 (Hz), used in latest researches. Using this system, a wider range of nonlinear viscoelasticity can be investigated.