A method for upgrading a network functions virtualization, NFV, application, comprising: creating, by a virtualized infrastructure manager, VIM, a network resource according to an upgrade plan for the NFV application; creating, by the VIM, a virtual machine for a new-version, VNF, according to the upgrade plan; configuring, by the VIM, the virtual machine on a test network according to the network resource; performing, by the VIM, upgrade configuration on the virtual machine according to an upgrade configuration script to obtain the new-version VNF; and switching, by an NFV orchestrator, NFVO, an earlier-version VNF to the new-version VNF after determining that a function test of the new-version VNF on the test network is successful; wherein the switching, by an NFVO, the earlier-version VNF to the new-version VNF comprises: instructing (251, 702-707), by the NFVO, the VIM to switch a network configuration of the new-version VNF, from the test network to a production network on which the earlier-version VNF is located; instructing (252, 708-713), by the NFVO, the VIM to switch a database corresponding to the earlier-version VNF to a database corresponding to the new-version VNF; instructing (253, 714-721), by the NFVO, the VIM to configure, in an earlier service load forwarding point corresponding to the earlier-version VNF, information about the new-version VNF, so that the earlier service load forwarding point manages traffic forwarding and load balancing of both the new-version VNF and the earlier-version VNF; and instructing (254, 722-729), by the NFVO, the VIM to switch a service of the earlier-version VNF to the new-version VNF. creating, by a virtualized infrastructure manager, VIM, a network resource according to an upgrade plan for the NFV application; creating, by the VIM, a virtual machine for a new-version, VNF, according to the upgrade plan; configuring, by the VIM, the virtual machine on a test network according to the network resource; performing, by the VIM, upgrade configuration on the virtual machine according to an upgrade configuration script to obtain the new-version VNF; and switching, by an NFV orchestrator, NFVO, an earlier-version VNF to the new-version VNF after determining that a function test of the new-version VNF on the test network is successful; wherein the switching, by an NFVO, the earlier-version VNF to the new-version VNF comprises: instructing (251, 702-707), by the NFVO, the VIM to switch a network configuration of the new-version VNF, from the test network to a production network on which the earlier-version VNF is located; instructing (252, 708-713), by the NFVO, the VIM to switch a database corresponding to the earlier-version VNF to a database corresponding to the new-version VNF; instructing (253, 714-721), by the NFVO, the VIM to configure, in an earlier service load forwarding point corresponding to the earlier-version VNF, information about the new-version VNF, so that the earlier service load forwarding point manages traffic forwarding and load balancing of both the new-version VNF and the earlier-version VNF; and instructing (254, 722-729), by the NFVO, the VIM to switch a service of the earlier-version VNF to the new-version VNF. instructing (251, 702-707), by the NFVO, the VIM to switch a network configuration of the new-version VNF, from the test network to a production network on which the earlier-version VNF is located; instructing (252, 708-713), by the NFVO, the VIM to switch a database corresponding to the earlier-version VNF to a database corresponding to the new-version VNF; instructing (253, 714-721), by the NFVO, the VIM to configure, in an earlier service load forwarding point corresponding to the earlier-version VNF, information about the new-version VNF, so that the earlier service load forwarding point manages traffic forwarding and load balancing of both the new-version VNF and the earlier-version VNF; and instructing (254, 722-729), by the NFVO, the VIM to switch a service of the earlier-version VNF to the new-version VNF.