Abstract: According to the special requirements of train control and passenger service business integration transmission in the train control and service network(TCSN), in view of data traffic scheduling in TCSN, this article comprehensively considered traffic characteristics, transfer demand of the various business traffic and utilization rate of the current network, designed a two-level scheduling policy DWDRR/PRI. The thought and the details of the two-level scheduling algorithm were expounded, the principle about how to solve the problem about critical business priority transmission and non-critical business fairness transmission according to the rules was introduced. Finally, the feasibility and correctness of the two-level scheduling algorithm was proved by simulation analysis.