The Border Gateway Protocol (BGP) is an important inter-domain routing protocol, which is widely used in Internet. It allows independent policies to be designed for each Autonomous System (AS). However, the flexibility in designing independent policies causes the convergence problem, i.e., a BGP network may constantly send routing information between ASes and cannot reach a stable state. In this paper, the authors propose an approach for model checking the convergence property of BGP networks. They firstly establish a formal model of BGP networks and define its convergence property.