This paper presents CDAP Algorithm,which is a beaconless node localization algorithm for wireless sensor networks..If non-beacon nodes exist,using of the improved clustering algorithm based on node density algorithm: ICAND algorithm to clustering,by the distributed localization method,combine the angle measurement and distance measurement,refer to the similar concept of time synchronization,gradually adjust the node position,and calculate all the coordinates of nodes in the regional coordinate system.Experiments show that the algorithm,in the case of randomly distributed nodes,CDAP algorithm has good performance in network coverage,positioning error and communication overhead rate,compared with clustering SPA algorithm which is industry-recognized.The network coverage is increased at least 51.3%.In addition,when the node density is larger than 0.9,the positioning error rate is reduced to 22.3% on the average.