To establish a database of communication optical cable length and geographical location, a vibration localization algorithm for phase-sensitive optical time-domain reflectometer（Φ-OTDR） based on wavelet packet denoising and feature projection is proposed. This algorithm uses Φ-OTDR for optical cable length positioning, effectively addressing the issue of interference signals in actual optical cable lines. By decomposing signals with wavelet packets and applying threshold methods for denoising, specific wavelet packets are selected based on the frequency characteristics of tapping vibration signals, using their energy as feature vectors for projection, which effectively demodulates vibration signals and suppresses interference. Test results show that compared to other algorithms, the proposed algorithm has lower complexity and superior performance, successfully applied to embedded devices, achieving precise tapping localization for 20 km of optical cable.