A call setup method is provided for a MVPN which includes at least one access point apparatus, at least one database, and a plurality of users. The database records a private extension number, a user phone number, and a user identity module of each user and a link address of the corresponding access point apparatus. The access point apparatus corresponding to a MO user receives a call setup request message for setting up a call with a MT user from the MO user. The access point apparatus corresponding to the MO user determines whether the link address of the access point apparatus corresponding to the MT user is valid according to the database. If the link address of the access point apparatus corresponding to the MT user is valid, the MO user and the MT user set up the call through the access point apparatuses corresponding to the link addresses.