A 2-D electromagnetic simulation model of the large gap magnetic drive system driven by traveling wave magnetic field was established, and the magnetic moment for the four pole-states when the angular displacement of the permanent magnet ranged from 0°to 360° was simulated with ANSYS software. In order to get the largest driving torque of the system, the concept of the best phase angle for the pole-state of the electromagnets was presented. The approximate formula for the best phase angle was drawn by analyzing the influence of the coupling distance and electromagnet-pole distance on the best phase angle of the system. The largest load torque of the axial-flow blood pump for different phase angles was calculated and compared by using load torque model through experiment. The results have shown that the best phase angles obtained through simulation can get the largest driving torque.