Bank systemic risk based on network model has recently became a hot topic． Due to the inaccessibility of interbank sensitive data，it is very difficult to make a breakthrough on it． This paper proposes a new method of analyzing interbank network characteristics． Firstly，this paper tests the distribution rule of interbank network node strength． Furthermore，we find out that interbank network node strength and its node degree follow the power function relationship． The paper proves that if node strength follows power law distribution，node degree also does． Finally，we deduce that China is characterized by scale-free interbank network with the highest concentration and the minimum scaling parameter compared with other countries.