<p>The high-precision machining of curved-thin-walled structures is challenging. As a typical one, miniature vortex curved thin wall with variable curvature is even more difficult and associated machining studies are very limited. Therefore, in order to guide the micromilling process optimization of the miniature vortex curved thin wall, this paper aims to build a force model in consideration of actual microcutting situations. Firstly, a model for instantaneous cutting thickness considering the influence of the trochoidal trajectory and tool runout is established. Secondly, a micromilling force prediction model for vortex curved surfaces is constructed by integrating the cutting edge elements taking part in cutting according to the tool-workpiece contact area. Thirdly, based on micromilling experiments of thin walls, the nominal milling force calibration method is used to calibrate the coefficients of the model. Then, the micromilling experiments of miniature vortex curved thin walls are carried out. A comparison between the measured micromilling forces and the predicted ones was conducted, with the errors mostly within 15%. Finally, under the guidance of the milling force model, a micromilling strategy with varied feed rates for different locations of the thin wall is provided. The deformation is successfully controlled and the thickness error of the thin wall is reduced to 2.83%. The model is applicable for predicting micromilling forces of different vortex curved surfaces by replacing the equation of the specific vortex curve to guide the process analyses for miniature vortex curved thin walls.</p>