1. An instant messaging communication method, comprising: inputting a first instant message and a first semantic tag of said instant message; encoding the first semantic tag in one of a header and a tail of the first instant message; transmitting the first instant message with the encoded first semantic tag; receiving a second instant message with a second semantic tag encoded in one of a header and a tail of the second instant message; constructing a visual topic structural diagram of the transmitted and received first and second instant messages according to the first and second semantic tags; and displaying the visual topic structural diagram.