Abstract: Internet topology data whose magnitude is 10⁷ in CAIDA was adopted to analyze the Internet network size， standard Internet structure entropy， Internet average path length， power exponents of degree distribution of IPv4，IPv6 and AS level Internet. The results showed that the Internet has expandability and robustness. The Internet topology has the elastic network characteristics， and the elastic network characteristics become more obvious with the evolution of Internet topology. The discovery of the Internet elastic network characteristics makes it possible for reference to biological macro guidance Internet topology research.

Key words: Internet topology, elastic network characteristics, expandability, robustness, vital signs