In view of the low output power and output efficiency exhibited by the conventional four-coil magnetic coupling contactless power transmission system, a planar spiral four- coil magnetic coupling contactless power transmission system has been proposed. A comparative analysis has been made between its output power and transmission distance, as well as its transmission efficiency and transmission distance by using MATLAB simulation software. The results show that,with the distance a constant, the output power and transmission efficiency of the planar spiral four-coil magnetic coupling contactless power transmission system are 3% higher than those of the traditional four-coil transmission system.