Business data was collected from 2000 automotive supply chain companies, establishes a multi-level supply chain network based on the gravity model, and establishes a "load" based on the flow between enterprises“capacity” model and proposed a multi-level directed network model for the load distribution process of failed nodes, and then simulate the risk of node failure propagation in the supply chain network to carry out robustness research. The experimental results show that the supply chain network constructed based on the gravity model has scale-free characteristics; in the multi-level supply chain network model based on the gravity model, the total traffic load of the node can be used as a measure of the importance of the node system; controllable coefficient And the maximum load factor has an important influence on the robust performance of the supply chain network. This paper provides research ideas for protecting important network nodes and improving the robust performance of the network in actual work.