The six degree of freedom (6-DOF) vibration platform is designed independently and it can simulate the actual operation of the vehicle to detect the vibration reducing performance of vehicle seat. The 6-DOF vibration platform could be applied to vehicle seat performance testing by the simulation experiment of road spectrum and the results of simulation analysis. First, calculating the Euler angles of each attitude of the vibration platform, the rotate matrixs at any moment were anslyzed and the inverse solution of the position and pose of the vibration platform was derived. In this way, the simulation of vehicle road spectrum was carried out. On the basis of the previous work, the rotate matrix algorithm was optimized further and the error of the two kinds of rotate matrix algorithm was analyzed with the aid of PROE simulation software. The simulation results show that the optimized algorithm makes the average value of the maximum error of the three points on the vibrate platform is reduced form 2.3 μm to 0.709 μm.