In order to accurately and quickly find the fault location of power transmission line in aerospace launch spot, the sensors are installed in transmission line to locate the fault position. These sensors are linearly distributed, which will lead to localization failure when the traditional DV-Hop algorithm is adopted to locate the sensor node. Therefore, an improved DV-Hop localization algorithm is put forward, which distributes the sensors of power transmission line in equal distance. The physical distance from unknown node to beacon node is acquired by calculating the minimum hop. The coordinates of unknown node are solved by hyperbola localization algorithm. Finally, through the application simulation, the results demonstrate that the localization accuracy of improved DV-Hop localization algorithm is higher than that of other traditional sensor localization algorithm, and its performance is more stable, which can realize the quick and accurate fault location of power transmission line in launch spot.