A policy decision function (PDF) addressing method includes: receiving a PDF allocation request that contains a user equipment (UE) identifier (ID) from a second network element (NE); obtaining ID information of a PDF associated with the UE ID according to pre-registered addressing information of the PDF, where the addressing information of the PDF is an association between the UE ID and the ID information of the PDF, and the PDF associated with the UE ID is accessed by a first NE; and sending the obtained ID information of the PDF to the second NE.