In this paper，the distributed abnormal vibration monitoring array in the distribution network is constructed based on the low reflectivity grating，and the phase signals demodulated by adjacent sensors are decomposed respectively. Then，the dynamic detection eigenvalues of spatial scale are constructed by the Hilbert transform of each mode function. When the distribution of eigenvalues fluctuates greatly，the abnormal vibration location and characteristics can be quickly and accurately located. The results show that the proposed method can quickly extract abnormal vibration features and effectively monitor the occurrence of abnormal vibration events with a period of 0.5 s，so it has certain application value in the monitoring of distribution network lines.