In optical burst switching (OBS) networks,contentions may occur at th e output port of an OBS core node when the incoming bursts contend the limited wavelength resources.Bur st retransmission can reduce data loss due to the burst contention in OBS core nodes.But un controlled retransmission may increase network load and data loss probability significantl .In addition,in a priority traffic existing OBS network,retransmission mechanisms should realize different services to support the quality-of-service (QoS) of the network.According to this,in this paper,we develop a controllable retransmission scheme based on prioritized burst segmentation.Different from previous works in the literature, we apply the prioritized burst segmentation and set a different value to retrans mission probability at each contention and control the total transmission times referred to the network load condition.In addition,we apply the proposed retransmission scheme to the prioritized burst segmentation f or QoS support.We take the load at each link due to both the fresh and the retransmit ted traffic into account.At last,we calculate the path blocking probability and the byte loss probability (ByLP) for different priority bursts to evaluate the network performance.The results have some theoretical significance for the designing of an OBS network.