The invention provides a resource sharing processing method, an apparatus and a P-CSCF. The method comprises the following steps of receiving a concurrent relationship information which is used for identifying two or more than two session services held by UE and is sent by a multimedia telephone application server MMTEL AS and/or the user equipment UE; according to the received concurrent relationship information, processing resource sharing among the two or more than two session services held by the UE. In the invention, a problem that the resources are wasted because there are a plurality of services, but only one service is activated and other resources are not released in a correlation technology is solved; therefore, effects of accurately triggering session service resource sharing and greatly increasing a network resource utilization rate are reached.