A session association method, comprising: collecting, by a collection module of a monitoring apparatus, call control signaling, on a signaling link of a control plane in a communications network, transmitted by network elements, wherein the call control signaling comprises speech channel information; characterized in that the communications network is a packet switched bearer network, the speech channel information is a user plane address, and a network element of a core network is not inserted into a user plane, collecting, by the collection module of the monitoring apparatus, call control signaling comprises collecting first call control signaling, on the signaling link of the control plane, between the network elements and a calling subscriber, and second call control signaling, on the signaling link of the control plane, between the network elements and a called subscriber; and the method further comprises performing, by an association module of the monitoring apparatus, session association on the call control signaling according to the speech channel information comprising performing session association on the first call control signaling and the second call control signaling according to the speech channel information to implement end-to-end association for a call/session mediated and relayed by a plurality of network elements, wherein the performing, by the association module of the monitoring apparatus session association on the first call control signaling and the second call control signaling according to the speech channel information comprises: if a first user plane address comprised in the first call control signaling and a second user plane address comprised in the second call control signaling are the same, performing session association on the first call control signaling and the second call control signaling. collecting, by a collection module of a monitoring apparatus, call control signaling, on a signaling link of a control plane in a communications network, transmitted by network elements, wherein the call control signaling comprises speech channel information; characterized in that the communications network is a packet switched bearer network, the speech channel information is a user plane address, and a network element of a core network is not inserted into a user plane, collecting, by the collection module of the monitoring apparatus, call control signaling comprises collecting first call control signaling, on the signaling link of the control plane, between the network elements and a calling subscriber, and second call control signaling, on the signaling link of the control plane, between the network elements and a called subscriber; and the method further comprises performing, by an association module of the monitoring apparatus, session association on the call control signaling according to the speech channel information comprising performing session association on the first call control signaling and the second call control signaling according to the speech channel information to implement end-to-end association for a call/session mediated and relayed by a plurality of network elements, wherein the performing, by the association module of the monitoring apparatus session association on the first call control signaling and the second call control signaling according to the speech channel information comprises: if a first user plane address comprised in the first call control signaling and a second user plane address comprised in the second call control signaling are the same, performing session association on the first call control signaling and the second call control signaling.