The invention discloses a method of realizing hierarchical network abstraction and a system. When a first controller uses an Openflow protocol to communicate with a second controller, a related virtual node identifier is added to an Openflow protocol message; the first controller sends the Openflow protocol message to the second controller; and after receiving the Openflow protocol message sent by the first controller, the second controller determines a virtual node related with the Openflow protocol message according to the node identifier included in the Openflow protocol message. Thus, in a condition in which only one Openflow protocol process is adopted between the first controller and the second controller, hierarchical network topology abstraction is realized, and a requirement of realizing multi-domain networking by adopting a hierarchical SDN controller architecture is met.