The present invention provides a security key change method and a user equipment (UE). The method performed by the UE includes: receiving a key change command message from a master eNodeB (MeNB), wherein the key change command message comprises an indication that a change of a security key between the UE and a secondary eNodeB (SeNB), and the UE is configured with a dual connectivity between the MeNB and the SeNB; updating a security key between the UE and the SeNB; performing random access to the SeNB; and sending a key change complete message to the MeNB.