Abstract: Network-on-chip (NoC) is a new interconnection structure which connects multiprocessors by network-based infrastructure. The data switching strategy between multiprocessors has great influence on the quality of service (QoS) of data transmission. A new switching structure which combines the dynamic virtual channels (VC) allocation and the dual-subnets infrastructure is proposed. The dynamic VC allocation is applied in order to increase the success-connection probability; while the dual-subnets infrastructure disperses data flows into XY-subnet and YX-subnet, avoids transmission congestion, and thus reduces packet transmission delay. The simulation results show that this Dyn-Dualnet-QoS strategy can provide great QoS guarantee for various levels of packet transmissions.