The invention relates to a span-region route control method of third-generation mobile communication system, which can make user consider the present call state when making span-region decision and registering at two regions, to route the following call to present region, to supply present service of each region to the user. Said method comprises: when the call requests route, the route decision inquire solid inquires present route decision from the RPDP; RPDP based on present route strategy and route decision, and the call states of user at CS and IMS region, fixes the route decision; RPDP feedbacks the fixed route decision and route relative information to the decision inquire solid, to over the span-region route control. |