Fluid jet polishing is an enabling ultra-precision machining technology, which has not only been widely used for removing machine tool marks in order to achieve super finished surfaces, but also for controlling the form accuracy in machining freeform surfaces. Due to the complex machining mechanism, it is difficult to model the material removal rate accurately with consideration of a lot of operational parameters in fluid jet polishing. In this article, the optimal operational parameters and the significance of the important parameters are determined by the Taguchi design of experiments. Hence, a computational fluid dynamics–based analysis is built for the determination of the material removal rate in fluid jet polishing. In this model, the impact information of the particles with respect to the workpiece is computed by computational fluid dynamics simulation which is then coupled with a local mechanics erosion model so as to predict the detailed distribution of the material removal rate in fluid jet polishing. To verify the computational fluid dynamics–based erosion model, a series of polishing experiments have been conducted. The experimental results are found to agree well with the predicted form error and the pattern of the material removal rate by the integrated erosion prediction model.