As we all know, the interdomain routing systems, based on BGP (Boarder Gateway Protocol, BGP), has become the core routing facilities of the Internet. However, due to their lack of the BGP security mechanism, BGP is vulnerable to all kinds of human configuration errors or malicious attacks. We develop a multilevel interdomain routing security monitoring system, and it can achieve four levels of domain routing, including the Internet, national network, a particular ISP and a specific route. This paper describes the system's composition structure, software structure, design, implementation technology and the achieved results.