A new automobile inertial parameters measuring device was designed to measure inertial parameters by using motions simulation of automobile roll, pitch, and yaw dynamics. Based on examining the structure, control strategy, and solution principle of the measuring device, the kinematic characteristics of the test device were analyzed by using multi-body dynamics method. The solution formulas based on rigid body rotation about a fixed axis were induced and the inertial parameters were calculated according to the experimental data. Since the dominating modal motion could cause vice modal motion, the solution formulas based on fixed-point rotation of rigid body considering coupled motions of the test device were established to verify the induced formulas. According to the experimental data, the inertial parameters were estimated by using nonlinear squares method. The estimated inertial parameters were compared with the calculated values and theoretical values. The analyzed results indicated that the calculation accuracy of automobile inertial parameters measuring device met the design needs.