The qualitative analysis of system power flow was made for articulated vehicle which had six independently-electric-driving wheels running in parallel under different driving states without following control. The system power flow model and wheel-motor power matrix were established. System power flow was described by using power bond graph and normalized power matrix. Taking torque as the control target, the test was performed to simulate the power flow state of permanent magnet synchronous motors running in parallel by means of adjusting voltage. Test analysis showed that the traction and braking power of the wheel-motor on both sides were equal when driving and electric braking straightly. The outside wheel-motors ran into regeneration state and produced braking torque when steering angle was large, then inside wheel-motors’ load were aggravating and theirs slip ratio increased. Speed ratio kn increased with the increasing of steering angle, but power ratio kP decreased at the same time. The severity of load had little effect on kn, Torque ratio kT of the rear axle was larger than the front axle and overload state was larger than light load state. 