Composite materials are widely used in civil aircraft structures due to their excellent properties. But composite structures may be subjected to internal damages caused by impact events, which can seriously degrade the property of the structures. So, it is critical to continuously monitor the impact of aircraft composite structures with low power consumption method. In this paper, a low power impact region localization method based on reverse weighted sum is proposed for airborne. The method is based on the principle of digital impact monitoring and the impact region localization is carried out according to the impact response digital sequences. The method is simple and efficient, and it is easy to program to the processor through embedded software. The power consumption, time and storage space of the processor are significantly reduced, which is beneficial to the low power design and application of the impact monitoring system. In addition, the method is applied to a low power miniaturized impact monitoring system, and experiment is carried out to verify the accuracy of impact region localization on the composite wing box structure. The evaluation results show that the low power impact monitoring method can accurately monitor each impact event, and the location accuracy is up to 96%.