A network handover method of a voice service, wherein the method comprises: receiving, by a mobility management network element in a first network, first information from an access network device in the first network, wherein the first information is used to indicate a handover of a terminal device from the first network to a second network, wherein the handover of the terminal device from the first network to the second network is a single radio voice call continuity, SRVCC, handover; skipping, by the mobility management network element in the first network based on the first information, an operation of sending a session management context request to a session management network element in the first network; and sending, by the mobility management network element in the first network, second information to a mobility management network element in a third network based on the first information, wherein the second information is used to instruct the mobility management network element in the third network to send a handover request to a mobile switching network element in the second network, and the handover request is used to hand over the voice service of the terminal device to the second network, wherein the handover request is a packet-switched to circuit-switched request message; wherein the first network is a fifth-generation, 5G, network, the second network is a second-generation, 2G, network or a third-generation, 3G, network, and the third network is an evolved packet system, EPS, network; wherein the mobility management network element in the first network is an access and mobility management function, AMF, network element, the mobile switching network element in the second network is a mobile switching center, MSC, network element, and the mobility management network element in the third network is a mobility management entity, MME, network element. receiving, by a mobility management network element in a first network, first information from an access network device in the first network, wherein the first information is used to indicate a handover of a terminal device from the first network to a second network, wherein the handover of the terminal device from the first network to the second network is a single radio voice call continuity, SRVCC, handover; skipping, by the mobility management network element in the first network based on the first information, an operation of sending a session management context request to a session management network element in the first network; and sending, by the mobility management network element in the first network, second information to a mobility management network element in a third network based on the first information, wherein the second information is used to instruct the mobility management network element in the third network to send a handover request to a mobile switching network element in the second network, and the handover request is used to hand over the voice service of the terminal device to the second network, wherein the handover request is a packet-switched to circuit-switched request message; wherein the first network is a fifth-generation, 5G, network, the second network is a second-generation, 2G, network or a third-generation, 3G, network, and the third network is an evolved packet system, EPS, network; wherein the mobility management network element in the first network is an access and mobility management function, AMF, network element, the mobile switching network element in the second network is a mobile switching center, MSC, network element, and the mobility management network element in the third network is a mobility management entity, MME, network element.