Embodiments of the invention disclose a method for security communication of carrier aggregation between base stations, which method comprises receiving, by a user equipment, a first message to add a cell controlled by a secondary base station as a service cell sent by a primary base station; and creating, by the user equipment, a security key for communication with cells controlled by the secondary base station according to security context of the primary base station and the first message. Embodiments of the invention further disclose the corresponding user equipment and base stations. Implementation of the method and apparatus according to the present invention makes it possible to effectively protect security of data transmission of the air interface and to avoid attacks on air interface security.