Method and system for realizing free conversation switching business

The invention provides a method and system for realizing free conversation switching business. The method comprises the steps of: in a process of keeping a conversation between a first terminal and a second terminal, transmitting a call request for the first terminal to call a third terminal to a free switching AS (Application Server) by an anchoring AS, wherein the first terminal is an anchoring terminal in a narrow-band network, and the first terminal and the third terminal sign the free conversation switching business in the free switching AS; and switching the third terminal to converse with the second terminal by the free switching AS according to the call request. The method and system provided by the invention solve the problem of failure of the free conversation switching business due to the protocol signaling limitation in the process of performing the free conversation switching business by a wide-band network terminal and a narrow-band network terminal in the prior art, so that free switching business between the anchoring terminal in the narrow-band network and the terminal in the wide-band network is realized, the success rate of the free conversation switching business is increased, and the user experience is improved.