The tunable-parameter deflection routing(TPDR) algorithm was proposed,which consists of the definition of a tunable-parameter(i.e.,deflection probability) to control the deflecting of contending bursts,and the nonlinear programming to search the optimum deflection path in terms of the burst loss probability(BLP) and the path length.The simulation results show that it can improve the overall BLP and the BLP of each individual priority,and reduce the offset-time deficit on QoS guarantee.