Abstract: In order to solve the problem of material removal in some specific regions of workpiece in softness abrasive flow machining, a method based on designing different restraint component structure to control flow field in constrained flow passage was proposed. A dynamic model of solid-liquid two-phase abrasive flow oriented to SAFM was established for physical parameters analysis by using standard k-ε model and Mixture model. Taking undulation and rectangle flow passages to be specific subject to emulate, some processing parameters were investigated, such as velocity and pressure. The results show that the value of turbulence kinetic energy in complex flow passage is larger than simple flow passage, so complex restraint components drive turbulence more random. Compared with rectangle flow passage, static pressure and dynamic pressure in the workpiece surface of undulation flow passage get increased and form differential pressure obviously according to the shape of restraint component. Processing parameters such as pressure, velocity, abrasive, incident angle, etc. can be changed by different restraint component and different cross-sectional area in flow passage, and small eddy can be produced to enhance machining precision. The processing parameters can be selected on the basis of numerical simulation results which were partly proved by experiment.