The present invention provides a method for controlling generation of routing information, a method for generating routing information, and apparatuses thereof. When it is detected that a virtual machine is migrated out of or migrated into a data center, a subnet to which the virtual machine belongs is determined, a route control identifier for adjusting routing information of a virtual machine that belongs to the subnet and is in the data center is determined, and the route control identifier is sent to the data center, so that the data center adjusts, according to the route control identifier, routing information of the virtual machine that belongs to the subnet and is in the data center. In this way, generation of many host routes in data centers when a virtual machine is migrated across the data centers is prevented.