Abstract: A low power mapping method was proposed in this paper for NoC mapping problem based on analyzing the relationship between communication power and communication flow.In order to low down the communication flow of NoC, the proposed method first uses approximated pre-mapping, which maps the larger communication flow IP core to the position close to other vertexes.In mapping step we use the result of pre-mapping step to search better solutions, which fulfills the mapping process from IP core in communication task graph to resource vertex in NoC architecture graph.Experimental results show that communication flow is decreased and it is effective to solve mapping problem with low power.