A dynamic wavelength management in an optical burst switching system guarantees QoS by using wavelength resources effectively and using only a basic offset time for guaranteeing a specified blocking loss rate without incurring any additional delay. A control header packet and data having a plurality of wavelengths are fed to a core node asynchronously, and the control header packet is processed in a control plane, during which a wavelength group list is created corresponding to a number of classes and the respective group list is dynamically reconstructed corresponding to each QoS group.