A network access apparatus, wherein the apparatus comprises: a ready-to-switch-network user equipment determining unit, configured to: determine a user equipment as a ready-to-switch-network user equipment according to an IP Multimedia Subsystem, IMS, function support status of the user equipment, UE, when registration in a circuit switched domain fails, wherein the IMS function support status is used to indicate whether the user equipment supports IMS voice; a target user equipment determining unit, configured to determine the ready-to-switch-network user equipment as a target user equipment according to a communication configuration parameter of the ready-to-switch-network user equipment, wherein the communication configuration parameter is used to indicate a preferred service type of the ready-to-switch-network user equipment; and a sending unit, configured to send a network switch indication carrying a preset cause value to the target user equipment determined by the target user equipment determining unit, wherein the network switch indication is used to instruct the target user equipment to access a voice service access network; wherein the ready-to-switch-network user equipment determining unit is further configured to: when registration in the circuit switched domain fails, if the user equipment supports an IMS function and does not establish an IMS bearer in a preset period, determine the user equipment as a ready-to-switch-network user equipment; wherein the target user equipment determining unit comprises: an acquiring subunit, configured to acquire the communication configuration parameter of the ready-to-switch-network user equipment determined by the ready-to-switch-network user equipment determining unit; and a determining subunit, configured to: when the communication configuration parameter acquired by the acquiring subunit is voice centric Voice Centric, determine the ready-to-switch-network user equipment as a target user equipment. a ready-to-switch-network user equipment determining unit, configured to: determine a user equipment as a ready-to-switch-network user equipment according to an IP Multimedia Subsystem, IMS, function support status of the user equipment, UE, when registration in a circuit switched domain fails, wherein the IMS function support status is used to indicate whether the user equipment supports IMS voice; a target user equipment determining unit, configured to determine the ready-to-switch-network user equipment as a target user equipment according to a communication configuration parameter of the ready-to-switch-network user equipment, wherein the communication configuration parameter is used to indicate a preferred service type of the ready-to-switch-network user equipment; and a sending unit, configured to send a network switch indication carrying a preset cause value to the target user equipment determined by the target user equipment determining unit, wherein the network switch indication is used to instruct the target user equipment to access a voice service access network; wherein the ready-to-switch-network user equipment determining unit is further configured to: when registration in the circuit switched domain fails, if the user equipment supports an IMS function and does not establish an IMS bearer in a preset period, determine the user equipment as a ready-to-switch-network user equipment; wherein the target user equipment determining unit comprises: an acquiring subunit, configured to acquire the communication configuration parameter of the ready-to-switch-network user equipment determined by the ready-to-switch-network user equipment determining unit; and a determining subunit, configured to: when the communication configuration parameter acquired by the acquiring subunit is voice centric Voice Centric, determine the ready-to-switch-network user equipment as a target user equipment. when registration in the circuit switched domain fails, if the user equipment supports an IMS function and does not establish an IMS bearer in a preset period, determine the user equipment as a ready-to-switch-network user equipment; wherein the target user equipment determining unit comprises: an acquiring subunit, configured to acquire the communication configuration parameter of the ready-to-switch-network user equipment determined by the ready-to-switch-network user equipment determining unit; and a determining subunit, configured to: when the communication configuration parameter acquired by the acquiring subunit is voice centric Voice Centric, determine the ready-to-switch-network user equipment as a target user equipment. an acquiring subunit, configured to acquire the communication configuration parameter of the ready-to-switch-network user equipment determined by the ready-to-switch-network user equipment determining unit; and a determining subunit, configured to: when the communication configuration parameter acquired by the acquiring subunit is voice centric Voice Centric, determine the ready-to-switch-network user equipment as a target user equipment.