Abstract: Identifying and measuring large flows is an important scalable solution for traffic measuring accurately on high-speed networks. A new algorithm based on LRU replacement scheme is proposed, which uses the policies of early dropping small flows and preparatively protecting large flows to enhance the accuracy of traffic measurement. An analysis demonstrates that the new algorithm can support the 10Gbps line-speed processing. Experiments are also conducted based on real network traces. Results show that the proposed method is more accurate and practicable than existing algorithms.