Disclosed is a system for performing key management of an in-vehicle network. The key management system of the in-vehicle network includes a reception unit configured to receive a shared secret key of a central gateway and a domain gateway, a memory configured to store a program for performing key management of the in-vehicle network using the shared secret key, and a processor configured to execute the program. The processor generates a secret key to be stored in a node of the in-vehicle network using the shared secret key and a unique ID of the node.