Emerging applications of RFID require high efficiency of tag identification. Since passive tags have dumb functionality, the efficiency of tag identification in RFID system relies on the performance of the collision arbitration algorithm embedded in a reader. In this paper, we develop a novel collision arbitration algorithm, which is named Q -Algorithm, improving Q-Algorithm which is introduced in a standard, EPCglobal Class-1 Generation-2. We maximized the efficiency of tag identification by modifying and optimizing the parameters used in Q-Algorithm. Simulation-based performance evaluation proves that our scheme shows the best identification efficiency among the diverse solutions.