To present a solution to the problem of address space exhaustion in the Internet, this paper proposes a multi-tier addressing architecture of the Internet (IPEA), illustrates the address space and addressing scheme of IPEA, defines the format of IP packet with extension address, and hierarchical routing algorithm. This paper analyzes and evaluates the performance of IPEA with simulation, and concludes that IPEA has such advantages: first, it provides a solution to the problem of address space exhaustion in the Internet; second, it reduces the routing table length, helps dealing with routing table explosion; third, it demands little change on the IPv4 addressing scheme, easy for transition; finally it makes the autonomous network more manageable by using private address.