A fundamental problem that confronts peer-to-peer applications is the efficient location of the node that stores desired data items. Chord protocol adopts finger tables to achieve (log Ο N) mean lookup path length for an N node system. To many time-sensitive applications, the requirement of optimal lookup path length is more critical. Our focus in this paper is to study how to shorten the lookup path length through optimizing routing protocol based on Chord. The contribution of this paper is a more efficient Chord-based routing protocol using neighbors’ neighbors links for lookup in a dynamic peer-to-peer system with frequent node arrivals and departures. Results from theoretical analysis and simulations show that both logical path length and physical end-to-end path latency of our protocol are shorter than Chord with the assist of neighbors’ neighbors links per node.