Wireless Personal Area Networks using UWB technologies have shown great potential as future home networks. In this paper we do some researches on the ARQ mechanism which provides the probability of involving the relay nodes into the UWB multi-hop wireless network. Based on the researches we design an ARQ mechanism combining Partial Window Multiple Rejects ARQ and Relay ARQ, which can perform on both the end nodes and the relay nodes. Then we make a theoretical analysis of the UWB wireless channel model and give a Markov model for the indoor UWB channel. With the simulation results, we can get the conclusion that using ARQ mechanism designed in this paper significant enhances the throughput and the wireless bandwidth utilization.