1. A processing method for service allocation, comprising: receiving, by a network device, service logic update information that is obtained after a configuration update is performed on a functional entity in a network; searching for initial service logic information already stored locally on the network device, and generating a system service logic policy according to the service logic update information and the initial service logic information; and sending the system service logic policy to service entities in the network that execute service processing, wherein the system service logic policy is used to instruct the service entities in the network to execute service allocation on the functional entity in the network.