The surface quality of the polishing tool is of great importance to the polishing performance, and it is usually maintained by a dressing process. The dressing parameters, which ultimately influence the effectiveness of dressing, are difficult to determine because the dressing process involves complex multiaxis motion control. To improve the machining efficiency and quality of the polishing tool, this study investigated the optimization of the process parameters. First, the grain on the grinding wheel was regarded as the research object. The trajectory model of the grain was established using multi-body theory. Subsequently, based on the above model, an optimization method was developed to optimize the process parameters. The experimental results showed that the average initial contour error of the surface of the polishing tools was 267.46 µm. When polishing tools were dressed using the worst process parameters, the surface quality was improved by an average of 67.82% to 86.06 µm. When polishing tools were dressed using the best process parameters, the surface quality of the polishing tools improved by 86.57% to 35.92 µm on average. This paper demonstrated the accuracy of the model and effectiveness of the proposed optimization method.