In this paper, we proposed and implemented an EPCglobal Reader Manegement (RM) based management protocol. Using RFID Reader's management function, we could diagnose an active RFID Reader concretely which was impossible with only using Reader protocols and check the problem quickly when the RFID Reader is in failure. When diagnosing RFID Readers using the proposed RM based management protocol, we can check on their failure in stages and specifically, and can estimate range of failure. This helps RFID Reader's fast recovery, reduce loss of failure and improve QoS. We could get reader information with almost same overhead compared with the management message in LLRP. And we could get more information about RFID Reader's operation status.