A method, an apparatus, and a system for processing a service flow, which belong to the field of communications. Correspondence between a service application attribute and a service application identifier is preconfigured on an NSP board so that after a service flow carrying the service application attribute is received, the service application identifier of the service flow may be determined, which service application corresponding to a service flow may be known according to the service application identifier corresponding to the service flow, and when a plurality of service applications is deployed on an NSP at the same time, a service flow can be correctly sent to a virtual machine of a corresponding service application for service processing.