<p>Abrasive waterjet (AWJ) milling is an unconventional technique that can be flexibly applied to a variety of difficult-to-process materials. However, developing a controllable AWJ milling process remains a significant challenge. This paper attempts to develop a model for predicting the cross-sectional profile of the workpiece processed by AWJ, which can assist in the optimization of the milling process. The profile extracted from the experiment is digitized, and the groove coordinate system is established to quantitatively analyze its geometric characteristics. The results indicate the presence of a smooth arc transition at the bottom of the groove, and thus, the profile geometry model is constructed according to the Gaussian function and the position of the inflection point. Furthermore, the material removal mechanism of AWJ is investigated, and a profile prediction model based on operational parameters is derived through dimensional analysis. In the validation experiment, the prediction error of the model is less than 5%, and the correlation coefficient (<i>R</i>²) between the predicted contour and the extracted contour is approximately 0.99.</p>