In this paper the method of approximate expansion is used to analyse a perfect planar surround sound system, resulting in an order of new and upgrade systems. First reproductinn signals of the perfect system and the characteristics of different orders systems are analysed. The independent transmission signals and decoding (reproduction) equation of the systexns are given. The compatibility among different orders systems and the problem of simplifying output channels are discussed. The problem of signal picking up, recording,transmitting and the possibility of putting the systems into practical use are studied. A sound hoage localization experiment for the systems is carried out in order to study haage localization in relaion to the numbers of transmission signals and output channels. The experimental result is consistemt with the theoretical result. This work lay down a base for practical use. In this paper the method of approximate expansion is used to analyze a perfect planar surround sound system, resulting in an order of new and upgrade systems. First reproductinn signals of the perfect system and the characteristics of different orders systems are analysed. The independent transmission signals The compatibility of different orders systems and the problem of simplifying output channels are discussed. The problem of signal picking up, recording, transmitting and the possibility of putting the systems into practical use are studied . A sound hoage localization experiment for the systems is carried out in order to study haage localization in relaion to the numbers of transmission signals and output channels. The experimental result is consistemt with the theoretical result. This work lay down a base for practical use.