Abstract: A new distributed slot assignment protocol to minimize end-to-end delay for multi-hop service-MRSA (Multi-hop Relay Slot Assignment) is proposed in this study. This protocol adopts a new multi-hop relay reserve mechanism to establish a virtual pipeline connected the source and destination node before relaying the multi-hop service data packets. Modeling analysis and simulation results showed that the MRSA can still make the effective slot assignment and reduce the end-to-end delay when compared with traditional Time Division Multiple Access (TDMA) protocol even under heavy traffic load.