The paper proposes a distributed bandwidth reservation protocol (DBRP) for QoS routing in ad hoc networks. The protocol adopts a TDMA-based model, derives from AODV, refers to the idea of three slot states (I.Jawhar et al., 2004), and adopts two-time reservation and controlling-flooding scheme. The protocol takes both the hidden-terminal and exposed-terminal problems into account. And it can solve the simultaneous reservation of several paths. In addition, controlling-flooding method can effectively control routing overhead, and two-time reservation can improve request success rate. Simulation results show the new protocol has better performance in denser networks and heavier traffic conditions.