To eliminate the shortcomings of existing Quality of Service (QoS) mechanisms such as Preemption and Wavelength Partition (WP) in Optical Burst Switch (OBS) networks, an improved QoS based label switching path(LSP) sharing (QLS) algorithm was proposed. QLS algorithm supports statistical multiplexing of wavelength resource by improving the performance of low priority service while ensuring transmission reliability and validity of the high priority service simultaneously. An open source discrete event simulation software OMNeT ++ based OBS/GMPLS simulation platform was created for WP and QLS algorithm in 4×4 symmetric MESH network and NSFNET network topology. Simulation results shows that for class3 service, QLS algorithm can improve packet loss ratio by 0.2 and 0.3 for MESH and NSFNET, while average packet loss ratio performance improved 0.05 and 0.1 respectively.