A topological learning method and apparatus for an OPENFLOW network cross a conventional Internet Protocol (IP) network. The method includes obtaining, by a controller, M OPENFLOW switch (OFS) ports connected to a same conventional IP network, determining whether there is a logical switch corresponding to the conventional IP network, if the controller determines that there is no logical switch corresponding to the conventional IP network, creating and storing the information about the logical switch, where the information about the logical switch includes related information of the M OFS ports, and related information of each OFS port includes link information in a direction from the port to the logical switch and/or link information in a direction from the logical switch to the port, and managing, by the controller, the logical switch as a common OPENFLOW switch of an OPENFLOW network.