A method for virtual network migration performed by a regional management entity, the method comprising: locating a source physical node in a regional physical network, wherein the regional physical network is composed of several physical nodes; obtaining at least one virtual element allocated to the source physical node, wherein each virtual element belongs to a different virtual network and each virtual element includes a virtual node and a virtual link born by the virtual node, and obtaining state information of each physical node in the regional physical network, wherein the state information comprises values for multiple capabilities of each physical node in the regional physical network; determining, according to the at least one virtual element and the state information, at least one physical node that can execute virtual network migration in the regional physical network, wherein a threshold is set for each of the multiple capabilities in the state information, and wherein the physical node that can execute the virtual network migration in the regional physical network has values for each of the multiple capabilities that are below the thresholds, wherein virtual network migration is a dynamic adjustment of a mapping relationship of a virtual network on a physical network; for each one of the at least one physical node that can execute virtual network migration performing the steps of: generating, for each virtual network,, a plurality of mapping relationships between each of the virtual elements of the virtual network and the physical node that can execute virtual network migration; comparing, for each virtual network, the generated mapping relationships; and selecting, for each virtual network, a mapping relationship with minimum migration consumption among the plurality of mapping relationships as a mapping relationship for executing migration; and sending, after performing for each of the at least one physical node the generating, comparing and selecting step, according to the mapping relationship for executing migration, a migration instruction to a physical node that needs to execute virtual network migration among the at least one physical node that can execute virtual network migration. locating a source physical node in a regional physical network, wherein the regional physical network is composed of several physical nodes; obtaining at least one virtual element allocated to the source physical node, wherein each virtual element belongs to a different virtual network and each virtual element includes a virtual node and a virtual link born by the virtual node, and obtaining state information of each physical node in the regional physical network, wherein the state information comprises values for multiple capabilities of each physical node in the regional physical network; determining, according to the at least one virtual element and the state information, at least one physical node that can execute virtual network migration in the regional physical network, wherein a threshold is set for each of the multiple capabilities in the state information, and wherein the physical node that can execute the virtual network migration in the regional physical network has values for each of the multiple capabilities that are below the thresholds, wherein virtual network migration is a dynamic adjustment of a mapping relationship of a virtual network on a physical network; for each one of the at least one physical node that can execute virtual network migration performing the steps of: generating, for each virtual network,, a plurality of mapping relationships between each of the virtual elements of the virtual network and the physical node that can execute virtual network migration; comparing, for each virtual network, the generated mapping relationships; and selecting, for each virtual network, a mapping relationship with minimum migration consumption among the plurality of mapping relationships as a mapping relationship for executing migration; and generating, for each virtual network,, a plurality of mapping relationships between each of the virtual elements of the virtual network and the physical node that can execute virtual network migration; comparing, for each virtual network, the generated mapping relationships; and selecting, for each virtual network, a mapping relationship with minimum migration consumption among the plurality of mapping relationships as a mapping relationship for executing migration; and sending, after performing for each of the at least one physical node the generating, comparing and selecting step, according to the mapping relationship for executing migration, a migration instruction to a physical node that needs to execute virtual network migration among the at least one physical node that can execute virtual network migration.