The flexure-based fast tool servo, which is well adopted to manufacture non-circular section parts, has attracted many researchers' attention for its cutting-edge characteristics in non-circular turning operation in terms of large output displacement, high bandwidth frequency, and fine surface processing. The geometric design and corresponding parameters configuration of the flexure hinge are deterministic to the performance of fast tool servo. In order to achieve a well-balanced stroke and natural frequency of the fast tool servo, this article proposes a harmony search-based multi-objective optimization method for setting of design parameters. Referring to the Lagrange method, the relationship between parameters of the flexure hinges and stiffness of the mechanism is derived and analyzed. Finite element analysis method is performed which demonstrates a fine agreement between the results from simulations and that from the proposed analytical solutions.