The present invention is a cross-domain routing control method. A routing policy decision point RPDP entity for saving routing policy information is arranged in a system which includes at least a circuit switched network and IMS domain. The method also includes: A the routing policy decision query entity queries the current routing policy to the RPDP entity when the call requests route; B the RPDP entity determines routing policy based on the current routing policy , information related to the routing policy and current calling state of the user in the circuit switched network and IMS domain; C the RPDP entity returns information related to route determined based on the determined routing policy to the routing policy decision query entity, the routing policy decision query entity completes the cross-domain routing control. The cross-domain routing control method of the present invention can control corss-domain routing based on calling state of the user in different domain.
