As the number of cores on a chip increases, power consumed by the communication structures takes significant portion of the overall power-budget. As technology scales to deep sub-micron processes, leakage power becomes increasingly significant as compared to dynamic power. In this paper, we design a power-aware switch including three operating modes, and they are normal mode, lease-line mode, and off mode. We can dynamically control the mode of switches in a NoC according to the profiling results of specific applications. We take MPEG-4 decoder as our case studies, and experimental results show that the total power saving of the NoC can be approximated to 90% if we dynamically control the switch mode when the communication characteristics of the embedded software are well known.