On the basis of analyzing on localization error of DV-Hop algorithm in WSN, an improved DV-Hop algorithm (ISSA-DH) combining hop distance improvement and sparrow search algorithm is proposed. Firstly, the accurate hop number is refined by communication radius, and the weighted correction factor is added to reduce the error of average hop distance; Then the hop distance is further weighted by the deviation between the estimated distance and the actual distance; Then the improved sparrow algorithm is used to replace the least square method, and the localization problem of wireless sensor is transformed into an optimal problem to obtain the position of the unknown node. Simulation experiments show that under different conditions, the localization error of ISSA-DH algorithm was reduced by 50.3% and 34.3% ,compared to the DV hop algorithm and improved algorithm (DCAI DV-Hop).