Closed-form solutions were developed to optimize kinematics design of a 2-degree-of-freedom (2-DOF) planar parallel manipulator. The optimum design based on the workspace was presented. Meanwhile, a global, comprehensive conditioning index was introduced to evaluate the kinematic designs. The optimal parallel manipulator is incorporated into a 5-DOF hybrid machine tool which includes a 2-D0F rotational milling head and a long movement worktable. The results show that the planar parallel manipulator-based machine tool can be successfully used to machine blades and guide vanes for a hydraulic turbine.