In order to make full use of the topological structure of wireless sensor networks（WSNs） to improve the node localization precision. A regulated density distance（RDD） algorithm based on node density weighting is proposed. The density weighting of all the nodes in the network are given. The distance between adjacent nodes is calculated by multiplying communication radius of node by the node density factor. In order to reduce the cumulative error

when the nodes are two hops

the path with the largest number of co-nodes among the nodes is selected as the optimal path and the distance between the nodes is calculated. When the nodes are multi-hops

the distance between the nodes is obtained by means of iterative accumulation. The beacon nodes are used to correct the distance. Improved particle swarm optimization algorithm is used to optimize the localization. The experimental results show that the proposed algorithm improves the positioning precision compared with the improved DV-Hop algorithm and the improved RND algorithm.