RFID is an essential technology in the Internet of things. Because it is a contactless, low power, and low cost wireless communication technology. During the process of tag identification, an efficient anti-collision algorithm will remarkably contribute to the RFID system in terms of accelerating identification speed. In this paper, a stack-like anti-collision algorithm is proposed, which is based on ISO 18000-6C. It can solve the problem of Q value fluctuation to some degree and improve the system efficiency.