Abstract: A new trajectory planning method for a new type parallel machine tool is proposed in this paper. This method plans trajectory in parameter space first, then the trajectory is mapped into joint space. The redundant degree of freedom of parallel machine tool is optimized with genetic algorithm, and the reciprocal of condition number of jacobian matrix is chosen as adapation degree function. Results of simulation and calculation show that this method can gain not only dexterious configuration but also steady kinematic characteristic.