In optical burst switching networks, burst retransmission can reduce data loss which is arising from the burst contention in optical burst switching core nodes, but uncontrolled burst retransmission may increase network load and data loss probability. A quality-of-service -supported controlled retransmission scheme was developed in optical burst switching networks. In this scheme, different values to retransmission probability were set at each contention and the total transmission times were controlled referred to the network load condition. In order to reach a balanced network load, the conflict bursts would no longer be retransmitted but be discarded when the number of burst retransmission reached our times. The path blocking probability and the burst loss probability for different priority bursts were calculated to evaluate the performance of the proposed scheme. From the simulation, with the retransmission probability and the number of retransmission increasing, it can be seen that burst loss probability is reducing while the path block probability is reducing. So it is necessary to control the retransmission probability and the number of retransmission. This result has some theoretical significance for the designing of an optical burst switching network test bed.