Abstract: With the development of wireless sensor network, WSN is obtaining a widely application as a new technology of acquiring and processing information. However, how to quickly locate the network nodes is also becoming an urgent problem in WSN system. This paper proposes a MDS locating algorithm based on the RSSI distance ratio. In the proposed algorithm, the distance matrix among those nodes is obtained by combining the RSSI distances ratio with the Euclidean distance measurement technique, and the global coordinate system is constructed via MDS analysis. Finally, the physics location of unknown nodes can be determined by coordinate transformation. The experiment results show that the proposed algorithm can effectively improve the accuracy of location and has important reference value for the development of high precision positioning system.