A new finishing technology of the swirling airflow compounded with magnetic-field is advanced. Machining prediction is carried through by simulating magnetic field and flow field. Abrasive velocity and grinding pressure according to injection pressure and abrasive diameter are shown. Unthreaded hole is experimented on the condition of adding magnetic field or not and the decrease of surface roughness on eight sampling points along axis is obtained. Research indicates that the swirling airflow compounded with magnetic-field finishing is feasible from the simulation and Adding magnetic field may avoid the ununiformity of finishing as well as increase finishing effect.