In the RFID system, a reader identifies tags by interrogating them through communications over a shared wireless channel Collisions occur when multiple tags transmit their IDs to the reader simultaneously, degrading the performance of tag identification. How to reduce tag collisions to speed up the identification procedure is thus important. There are several protocols: proposed for avoiding tag collisions. They can be categorized into three classes: ALOHA-based, tree-based and counter-based Among them, the counter-based protocols have comparable high performance. In this paper, we propose a counter-based anti-collision protocol using the concepts of adaptive k-way splitting and pre-signaling. We also conduct simulation experiments for the proposed protocol and compare it with ISO/IEC 18000-6B anti-collision protocol to demonstrate its advantages.