Method for constructing wide-area mobile communication security private network capable of supporting international roaming

The invention discloses a method for constructing a wide-area mobile communication security private network capable of supporting international roaming. The method comprises the following steps that: a public network of an operator is divided into an access network and a core network, and existing core networks of domestic and overseas operators are defined as core network visit domains of a security private network; a self-established core network is established by industry self-establishment or the combination of the industry and the operator, and the self-established core network is divided into a non-roaming scene and a roaming scene according to different access positions of mobile users; in the non-roaming scene, mobile users are locally accessed through a base station of a location where the self-established core network is located, and the self-established core network is defined as a complete core network of the security private network; and in the roaming scene, the mobile users are not locally acce