The invention provides a method and a device for signaling path optimization and an application server, and relates to the field of a core network. The method for signaling path optimization comprises the steps of obtaining a call connection request for calling a called number by a calling number in a same network type, wherein the call connection request carries a TRF (Transit and Roaming Function) head domain of the calling number and/or the called number; determining the attribution of the calling number and the attribution of the called number based on the call connection request; and when the attribution of the calling number and the attribution of the called number are the same attributions, deleting the TRF head domain, and building call connection between the calling number and the called number by using a call connection signal of a calling attribution device. Therefore, signaling detouring is reduced, extra time delay for putting through is also accordingly reduced, and the experience effect of a user is also improved.