Embodiments of the present invention provide a scale-out association method and apparatus, so as to implement a scale-out association operation between VNFs. After initiating a scale-out, a first VNF sends a scale-out notification message to a second VNF that is directly associated with the first VNF. The scale-out notification message of the first VNF carries a scale-out magnitude parameter of the first VNF. The second VNF determines, according to the scale-out magnitude parameter of the first VNF and a service processing capability of the second VNF, whether the second VNF needs to be scaled out. If it is determined the second VNF needs to be scaled out, then the second VNF sends a scale-out request message to a VNFM.