The migration method includes dividing each service system in a first cloud system into a plurality of modules; determining the relation between a module to be migrated among the plurality of modules and other modules; copying said module among the plurality of modules to a second cloud system, the type of the first cloud system being different from that of the second cloud system; and establishing a relation in the second cloud system to complete the migration of the first cloud system. The nature and gist of the present disclosure is that the migration of a module to be migrated in the first cloud system is completed by establishing the association relation of the module to be migrated in the second cloud system.