An SLA-based resource allocation method, comprising: • receiving, by a Network Functions Virtualization Orchestrator, NFVO, a network service instantiation request, wherein the network service instantiation request comprises an identifier of a Service Level Agreement SLA of a network service (S 101); • determining, by the NFVO based on the identifier of the SLA of the network service, a Network Functions Virtualization Infrastructure, NFVI, SLA parameter required for instantiating the network service (S 102); • obtaining, by the NFVO from a Virtualized Infrastructure Manager, VIM, based on the NFVI SLA parameter, a virtual resource meeting a requirement of the NFVI SLA parameter (S 103), wherein the obtaining, by the NFVO from the Virtualized Infrastructure Manager, VIM, based on the NFVI SLA parameter, the virtual resource meeting the requirement of the NFVI SLA parameter comprises: o determining, by the NFVO based on the NFVI SLA parameter and SLA parameter information of NFVI resource pools obtained from the VIM in advance, information about the virtual resource meeting the requirement of the NFVI SLA parameter in the NFVI resource pools; o sending, by the NFVO, a resource request message to the VIM, wherein the resource request message comprises the information about the virtual resource, and the resource request message is used to query availability of the virtual resource and reserve the virtual resource; and o receiving, by the NFVO, a resource response message sent by the VIM, the resource response message being used to indicate the reservation of the virtual resource; and • instantiating, by the NFVO, the network service based on the obtained virtual resource (S 104). • receiving, by a Network Functions Virtualization Orchestrator, NFVO, a network service instantiation request, wherein the network service instantiation request comprises an identifier of a Service Level Agreement SLA of a network service (S 101); • determining, by the NFVO based on the identifier of the SLA of the network service, a Network Functions Virtualization Infrastructure, NFVI, SLA parameter required for instantiating the network service (S 102); • obtaining, by the NFVO from a Virtualized Infrastructure Manager, VIM, based on the NFVI SLA parameter, a virtual resource meeting a requirement of the NFVI SLA parameter (S 103), wherein the obtaining, by the NFVO from the Virtualized Infrastructure Manager, VIM, based on the NFVI SLA parameter, the virtual resource meeting the requirement of the NFVI SLA parameter comprises: o determining, by the NFVO based on the NFVI SLA parameter and SLA parameter information of NFVI resource pools obtained from the VIM in advance, information about the virtual resource meeting the requirement of the NFVI SLA parameter in the NFVI resource pools; o sending, by the NFVO, a resource request message to the VIM, wherein the resource request message comprises the information about the virtual resource, and the resource request message is used to query availability of the virtual resource and reserve the virtual resource; and o receiving, by the NFVO, a resource response message sent by the VIM, the resource response message being used to indicate the reservation of the virtual resource; and o determining, by the NFVO based on the NFVI SLA parameter and SLA parameter information of NFVI resource pools obtained from the VIM in advance, information about the virtual resource meeting the requirement of the NFVI SLA parameter in the NFVI resource pools; o sending, by the NFVO, a resource request message to the VIM, wherein the resource request message comprises the information about the virtual resource, and the resource request message is used to query availability of the virtual resource and reserve the virtual resource; and o receiving, by the NFVO, a resource response message sent by the VIM, the resource response message being used to indicate the reservation of the virtual resource; and • instantiating, by the NFVO, the network service based on the obtained virtual resource (S 104).