Embodiments of this application provide a common service resource application method, a related device, and a system. The method includes: receiving, by a common service manager (CSM), resource requirement information of a common service required by a virtual network function (VNF); and then requesting, based on the resource requirement information of the common service required by the VNF, a virtualized infrastructure manager (VIM) to allocate a resource required by the common service of the VNF. In some embodiments, the CSM applies to the VIM for the resource of the common service required by the VNF, so as to avoid the VNF not working or service quality deteriorating because the common service has no available resource or resources are insufficient, and to avoid wasting common service resources.