A system for virtual machine, VM live migration, characterized in that, the system comprising a management node, a source server, a destination server, a peripheral component interconnect express, PCIE switch, and a single root I/O virtualization, SR=IOV network adapter, wherein: the source server, the destination server, the management node, and the SR-IOV network adapter separately connect to a physical port of the PCIE switch to perform communication; the source server comprises a virtual machine before live migration, and the virtual machine before live migration is a source end of the virtual machine live migration; the SR-IOV network adapter comprises a physical input/output port and multiple virtual function, VF modules, wherein the physical input/output port is configured to connect to one physical port of the PCIE switch to perform communication; the management node is adapted to establish, before the virtual machine live migration, a connection relationship between a VF module used by the virtual machine before live migration on the SR-IOV network adapter and the source server by configuring the PCIE switch, and establish, after the virtual machine live migration, a connection relationship between the VF module used by the virtual machine before live migration on the SR-IOV network adapter and the destination server by configuring the PCIE switch; and the destination server comprises a virtual machine after live migration, the virtual machine after live migration is a destination end of the virtual machine live migration, and a virtual machine monitor of the destination server is configured to: by using the PCIE switch and according to the connection relationship with the VF module used by the virtual machine before live migration configured by the management node, use the VF module used by the virtual machine before live migration to complete the virtual machine live migration. the source server, the destination server, the management node, and the SR-IOV network adapter separately connect to a physical port of the PCIE switch to perform communication; the source server comprises a virtual machine before live migration, and the virtual machine before live migration is a source end of the virtual machine live migration; the SR-IOV network adapter comprises a physical input/output port and multiple virtual function, VF modules, wherein the physical input/output port is configured to connect to one physical port of the PCIE switch to perform communication; the management node is adapted to establish, before the virtual machine live migration, a connection relationship between a VF module used by the virtual machine before live migration on the SR-IOV network adapter and the source server by configuring the PCIE switch, and establish, after the virtual machine live migration, a connection relationship between the VF module used by the virtual machine before live migration on the SR-IOV network adapter and the destination server by configuring the PCIE switch; and the destination server comprises a virtual machine after live migration, the virtual machine after live migration is a destination end of the virtual machine live migration, and a virtual machine monitor of the destination server is configured to: by using the PCIE switch and according to the connection relationship with the VF module used by the virtual machine before live migration configured by the management node, use the VF module used by the virtual machine before live migration to complete the virtual machine live migration.