The present invention discloses a method for selecting policy decision functional entity in the Resource and Admission Control System. The method includes that: for resource and admission control in the PULL mode, after the Transport Resource Control Function Entity (TRC-FE) receives a resource request message from the Customer Premises Equipment (CPE) or after the Policy Enforcement Function Entity (PE-FE) receives a transport layer signaling sent by CPE, if the TRC-FE or PE-FE is interacting with more than one Policy Decision Functional Entities (PD-FEs), the TRC-FE or the PE-FE may select a PD-FE according to the stored identification information of PD-FE or statically configured PD-FE, and send a resource decision request message to the selected PD-FE. With the application of the present invention, in resource and admission control in the PULL mode, after receiving the resource request initiated by CPE through the transport layer signaling message, the TRC-FE or PE-FE may select the exact PD-FE to implement the resource reservation process, thereby resolving the problem in prior art that during the resource and admission control process the TRC-FE or PE-FE can not select the exact PD-FE to send resource decision requests.