Abstract: The test principle of a new six-freedom tire test bench and analytical method of tire load were studied. Using multi-body dynamics theory and rotational transformation matrix, the actuator lengths of tire test conditions were obtained. Considering the directions of the actuator forces, the force sensor measurement, the actuator vector, and the rotational transformation of the tire force when there was a side slip angle, the tire forces in three directions were solved. Using the actuator force vector, the vector of each actuator arm and the space vector operation, the tire moments were solved. A simulation model of the tire test bench was built. The camber test and the side slip test were simulated. Simulation results show that the solution method of the actuators motion law is correct. The tire multi-condition test was simulated. Simulation results indicate that the solution method for the six components computation of tire load is feasible.