A method for inter-system handover is provided by the present invention, including: changing a first handover-related information into a second handover-related information, wherein the first handover-related information is supported by a serving communication system and the second handover-related information is supported by a target communication system; and handing over the user terminal from the serving communication system to the target communication system based on the second handover-related information. An apparatus for inter-system handover is also provided. The present invention can insure successful handover of user terminals from a serving communication system to a target communication system.