The invention discloses a power distributing method for a network-on-chip of a multi-core processor. The method comprises the steps of setting a dynamic power consumption model of network-on-chip routers of the multi-core processor and a performance model of the network-on-chip; under the circumstance that the consumed total power of the network-on-chip routers is fixed, calculating the optimal working frequency of the network-on-chip routers through a dynamic programming algorithm; and carrying out power distribution on every router of the network-on-chip according to the optimal working frequency to ensure that the network delay of the data package transmission of the network-on-chip is minimum. The method disclosed by the invention has the advantages that the fine-granularity power distribution is quickly carried out on the routers in real time according to the workloads of the routers, so that the minimum network delay of the data package transmission is realized, the overall performance of the network-on-chip achieves the best, the power consumption of chips is lowest and the purpose of optimal energy management is achieved.