Abstract: An optimal kinematic design strategy of high-speed parallel robots is proposed based on performance of mechanism singularity and motion transmission. The presented method can be implemented in two steps. In the first step, a non-dimensional parameter design space is constructed. Within the design space, the available workspace and singularity of 3-RRR are then studied and the distribution characteristics of singularity loci are analyzed. The ranges of design parameters, which constitute 3-RRR manipulator free of internal singularities, are thereby obtained. In the second step, the kinematic parameters are optimized by considering global condition index as objective function and the transmission angle as constraint condition. 3-RRR parallel robot is designed using this method. The experimental result shows that the designed robot has excellent motion transmissibility.