Abstract: At present, the security threat of industrial Internet data is becoming more and more serious. Effective network transmission plays a key role in the data security of industrial Internet. In order to effectively adapt to the structure of the industrial Internet and achieve safe and reliable communication, a key management scheme based on blockchain dynamic nodes is proposed. In industrial communication, an effective session key needs to be established between untrusted nodes, and the traditional key agreement is realized by using a central node in the way of middleman. However, Once the central node fails, the communication of the whole communication system will fail. When the number of nodes n is small, the central node is usually used to set the key in advance. Each node needs to store (n-1) keys, so the whole system needs to store n(n-1) keys. Once the nodes need to be increased, the keys stored in the whole system will increase exponentially. Therefore, based on the blockchain, we use polynomials to construct communication keys, decentralize to generate shared keys, effectively resist the threat of node access to the system, and ensure effective group key negotiation. The propsosed scheme has faster processing speed than that of traditional PKI. If any node loses its key, it can effectively recover the original key with the help of other node information.