On the basis of rheological behaviors of abrasive flow, the stress tensor was analyzed to explore the micro-cutting force of the Abrasive Flow Machining (AFW) process. It points out that the abrasive flow precision machining is a combined machining method made by extrusion and micro removal, and the micro-cutting force of the AFW is come from a combination of medium share force, squeezing force and plowing force. The dynamics model was established and general change law of the micro-cutting force in AFW processing were revealed quantitatively by changing processing conditions and processing parameters, such as the pressure of contact region, removal amounts and surface roughness. Finally, the shear force was simulated numerically by using the CFD module of COMSOL multiphysics software. The experiment results show that the mold core is conductive to increasing the micro-cutting force, the surface roughness Ra of the solider (number four) has decreased from 2.918 μm to 1.027 μm and the removal is 0.09 g after 15 processing cycles. The results demonstrate that the removal is changed in the abrasive flow machining process, however, the removal action is quick weakened with the increase of the times of extrusion and the surface roughness is still improved.