A method of handling an access network discovery and selection function (ANDSF) for a network of a wireless communication system is disclosed. The method comprises determining a first plurality of closed subscriber group (CSG) cells of the wireless communication system with a first CSG identity, for a mobile device of the wireless communication system to communicate with an evolved packet core (EPC) network of the wireless communication system via the first plurality of CSG cells, after the network determines the 3rd Generation Partnership Project (3GPP) as an access technology for the mobile device; and configuring an inter-system mobility policy (ISMP) node such that a value of an AccessTechnology leaf of a PrioritizedAccess node is configured as the 3GPP, and a value of a first AccessId leaf of the PrioritizedAccess node is configured as the first CSG identity of the first plurality of CSG cells.