Optical burst switching (OBS) has been considered as one of the promising technologies for the next-generation optical internet.In OBS networks,packets are assembled into bursts at ingress nodes,and the burst head packet reserves suitable wavelength o n the links for the corresponding data burst by using a scheduling algorithm in the core node.Once the burst head packet fails to reserve resource for the corresponding burst,the burst will be dropped,and it must influence the network′s performance.This paper proposes a l abeled-based preempted scheduling algorithm,where the burst head packet is used in schedule channel for different service classes dat a burst.Through the difference of traffic occupying bandwidth resources,the algorithm ado pts different scheduling methods to meet different traffic′s requirements,thus can select sui table channel for the data burst.From the simulation results,we can see that the algorithm can r educe the burst blocking probability and enhance the channel utilization,so it can promote the performance of OBS networks.