To effectively reduce the burst loss probability(BLP) and guarantee the quality of service(QoS) with different priority bursts,a burst segmentation-optical buffer contention resolution mechanism based on priority in optical burst switching(OBS) networks is proposed.The fiber delay units are intercalated to buffer the segmented part of bursts in the output data channels of a multi-wavelength channel system.When the competition occurs,the header of competition burst data packet or the tail of original burst data packet is segmented according to the priority and the processing time of bursts.The collision-free parts are exchanged or directly output in the reserved output data channel.Segmented bursts are buffered in the optical buffer.Simulations show that the burst loss probability of the high-priority is much less than that of the low-priority bursts in a multi-wavelength channel system.The mechanism also can efficiently reduce the end to end transmission delay and the burst loss probability of entire networks,so it can improve the performance of OBS networks.