In order to improve precision of grinding as well as accuracy of ball nose end mills, the Taguchi approach was adopted to figure out quasi-optimal parameter values of the XYZ axes drives and the controller for a five-axis tool grinder. Firstly, the backlash and pitch errors of the transmission system and rotational axes were measured via a laser interferometer, and these errors were compensated by setting compensation values on a human machine interface of the controller. Four control factors with three levels and an L9 orthogonal array were used in the experiments, and each experiment was repeated three times. Next, this parameter design was applied to obtain quasi-optimal values of the drives and the controller, and further a tool grinder was employed to grind five ball nose end mills to confirm the practicability. Finally, a tool measuring and inspection machine was utilized to measure the tool geometry of each end mill for the initial and optimal designs. Experimental results were shown to indicate the considerable improvement of the accuracy of the end mills and demonstrate the effectiveness of our proposed scheme.