A method for implementing a trunk service, wherein the method comprises: Receiving, by an interworking function entity, IWF, uplink control plane signaling or uplink control plane signaling and uplink user plane media data sent by a trunking terminal UE; performing, by the IWF, encapsulation and conversion on the uplink control plane signaling or the uplink control plane signaling and the uplink user plane media data, and sending the uplink control plane signaling or the uplink control plane signaling and the uplink user plane media data after the encapsulation and conversion to a trunk control function entity, TCF; receiving, by the IWF, downlink control plane signaling or downlink control plane signaling and downlink user plane media data sent by the TCF; and performing, by the IWF, encapsulation and conversion on the downlink control plane signaling or the downlink control plane signaling and the downlink user plane media data, and sending the downlink control plane signaling or the downlink control plane signaling and the downlink user plane media data after the encapsulation and conversion to the UE; characterized in that the receiving, by an IWF, uplink control plane signaling and uplink user plane media data sent by a trunking terminal UE comprises: receiving, by the IWF from a default bearer in a trunking access subsystem, the uplink control plane signaling sent by the UE, and receiving, from a dedicated bearer, the user plane media data sent by the UE, wherein the default bearer and the dedicated bearer are a default bearer and a dedicated bearer on a packet data network, PDN, connection established by the UE to a dedicated access point APN corresponding to a trunk. Receiving, by an interworking function entity, IWF, uplink control plane signaling or uplink control plane signaling and uplink user plane media data sent by a trunking terminal UE; performing, by the IWF, encapsulation and conversion on the uplink control plane signaling or the uplink control plane signaling and the uplink user plane media data, and sending the uplink control plane signaling or the uplink control plane signaling and the uplink user plane media data after the encapsulation and conversion to a trunk control function entity, TCF; receiving, by the IWF, downlink control plane signaling or downlink control plane signaling and downlink user plane media data sent by the TCF; and performing, by the IWF, encapsulation and conversion on the downlink control plane signaling or the downlink control plane signaling and the downlink user plane media data, and sending the downlink control plane signaling or the downlink control plane signaling and the downlink user plane media data after the encapsulation and conversion to the UE; characterized in that the receiving, by an IWF, uplink control plane signaling and uplink user plane media data sent by a trunking terminal UE comprises: receiving, by the IWF from a default bearer in a trunking access subsystem, the uplink control plane signaling sent by the UE, and receiving, from a dedicated bearer, the user plane media data sent by the UE, wherein the default bearer and the dedicated bearer are a default bearer and a dedicated bearer on a packet data network, PDN, connection established by the UE to a dedicated access point APN corresponding to a trunk. receiving, by the IWF from a default bearer in a trunking access subsystem, the uplink control plane signaling sent by the UE, and receiving, from a dedicated bearer, the user plane media data sent by the UE, wherein the default bearer and the dedicated bearer are a default bearer and a dedicated bearer on a packet data network, PDN, connection established by the UE to a dedicated access point APN corresponding to a trunk.