Aiming at the problem that the equipment of wireless sensor network ranging distance is short and the positioning accuracy is not high, MDSMAP positioning algorithm based on pseudo random code correlation is proposed. Firstly, the ultrasonic signal emitted from the node is coded by using the pseudo random code correlation detection technology, the node distance and the accuracy are effectively increased. For a node failed to measure the distance, which is processed by using the Euclidean and the shortest path fusion algorithm, and then relative coordinate of node is generated by using the relative coordinates of MDSMAP algorithm. Finally, the final coordinate of node is obtained by using the plane transform model. The experiment results of simulation show that the improved algorithm can achieve a higher positioning accuracy and smaller positioning error under different network size and distance error conditions.