Optical burst switching (OBS) has been proposed as a promising switchi ng technology for the next generation of optical transport networks.Particular attention is paid to the co mmercial OBS networks with sparse wavelength conversion capabilities (SWCC-OBS).An overall burst packet loss pro bability,which adequately represents the congestion state of entire network,is the primary metric of inter est in an SWCC-OBS network.With the overall loss probability as the optimization objective,a novel routing mode l is proposed based on integer non-linear programming formulation.In order to overcome the computational comp lexity,a novel routing algorithm based on decomposition coordination is proposed to solve the problem b y decomposing and pre-forecasting the variables.Also it updates the values according to the feek back.Finally,it will obtain an optimal routing path and the global approximate optimal path to minimize the burst los s probability.The simulation results show that the proposed model and algorithm can give a near-optimal rout ing that avoids the conflict of burst data effectively and decreases the overall burst loss probability.At the same t ime,it also performs well in balancing payloads throughout the whole network under different kinds of burst data patter ns and network topologies.