An anchor key generation method, device, and system, where the method includes generating, by a unified data management network element (UDM), an intermediate key based on a cipher key (CK), an integrity key (IK), and indication information regarding an operator; sending, by the UDM, the intermediate key to an authentication server function (AUSF); receiving, by the AUSF, the intermediate key; generating, by the AUSF, an anchor key based on the intermediate key; sending, by the AUSF, the anchor key to a security anchor function (SEAF); and generating, by the SEAF, a key (Kamf) based on the anchor key, where the Kamf is used to derive a 3rd Generation Partnership Project (3GPP) key.