For Inter-APN routing flow distribution, a step of receiving, by a UE from a server, an Inter-System Routing Policy (ISRP) rule that comprises flow distribution rules for at least one of a For Flow Based flow distribution container used for IP Flow Mobility (IFOM), a For Service Based flow distribution container used for Multi-Access PDN Connectivity (MAPCON), a For Non-Seamless Offload flow distribution container used for Non-Seamless WLAN Offload (NSWO), and an Inter-APN routing flow distribution container, is performed. Here, the Inter-APN routing flow distribution container comprises information related to routing IP flows with respect to a plurality of APNs for using PDN connections to access multiple IP networks. Then a step of selecting, by the UE, among active/valid flow distribution rules in the received ISRP rule, a flow distribution rule having highest priority is performed.