A high speed tracking control system for 6-6 Stewart platform manipulator is designed for performing the model based joint-axis sliding mode control. Because of the complex dynamics and kinematics of the Stewart platform manipulator, two computer systems, consisting of a PC and a DSP, are adopted, so that real time tasks are run in synchronous and asynchronous modes. It is experimentally proven that the proposed control system makes the convenience in implementation of model based tracking control, so that it can achieve effective tracking control under relatively high speed and additional payload conditions.