Implementing method, system and apparatus for IMS listening

An embodiment of the invention discloses a method for realizing IMS monitoring, a system and a device thereof, wherein the method comprises the following steps: allocating a medium anchoring point for the communication sides; and duplicating the communication content when the communication sides do communication through the medium anchoring point for completing the monitoring to the communicationcontent. According to the invention, the monitoring to the communication content can be realized on the medium anchoring point and is not compulsorily realized by the existing medium access device, thereby realizing the centralized monitoring of medium on IMS and ensuring that the subscribers which are accessed into the IMS with various modes can realize centralized monitoring of medium on the IMS core. No requirement exists for the access side device, and furthermore expanded private interface is not required between the IMS core and the access side device.