Abstract: DV-Hop algorithm is one of the classical localization algorithms in wireless sensor networks. It has a low cost and is easily implemented, but its precision is low. Based on the trilateral method or the maximum likelihood estimation method, the third step which is used to obtain the location of the unknown node is corrected. Subtraction after square is adopted when we solve the equation set in the third step. To improve the localization error due to more than one hop, we set the hop count as the weighted value, and then the resulting weighted matrix is designed. With the weighted least square method introduced, the location of unknown nodes is refined with the extraneous information obtained by solving the equations. The theoretical analysis and simulation results show that the improved method can effectively improve the positioning accuracy, and can also be applied in the actual scene.