Localization is very important for the applications in wireless sensor network. For the disadvantage that the accuracy of traditional DV-Hop algorithm is low, this paper proposes an improved DV-Hop localization algorithm named NDV-Hop (Novel improved DV-Hop algorithm). NDV-Hop takes some improvements over DV-Hop from the following aspects: firstly, average hop distance is calculated by taking all the beacon nodes into account. Secondly, the position information of unknown nodes is amended by adopting error value of the beacon nodes. Finally, the position information that the out-of-scope node is revised by taking boundary coordinates as its position information. The results of simulation experiment show that the relative error of NDV-Hop is lower than that of DV-Hop. NDV-Hop can satisfy the requirement of actual practice better.