A redistribution rule of failed load based on this capacity of nodes is given. And a cascading failure of model is built based on the rule and the structure features of network. Then the invulnerability of network from different perspectives such as parameter ??, the types of nodes and the network structure are analyzed and researched. The simulation results show that the failure of relaying nodes will cause more serious damage to the invulnerability of network, and it can enhance the
invulnerability of network by increasing the value of parameter ?? and the network complexity.