Abstract: In order to understand deeply invariant characteristics and dynamic laws of the Internet complex giant system，the characteristics of the Internet topology at autonomous system level are analyzed.The mathematics definition of the power-law distribution and the scale-free criterion，along with the relations between them are given.The main properties of the small-world network，i.e.the short average path length and the large clustering coefficient，are studied，and the assortativity and the rich-club phenomenon are discussed.Based the above theoretical results，the maximum node degree，the average node degree，the clustering coefficient and the maximum clique size of the topology of the Internet Autonomous System（AS） are calculated using experiential data collected from BGP protocol.The power-law distribution，disassortativity and rich-club phenomenon of the Internet AS are tested and verified，and the power exponent and assortativity coefficient and rich-club coefficient are obtained.