Distributed optical fiber perimeter security systems is vulnerable to external a nd has high false alarm rate. For characterizing the differences of the system output signal in the time-freq uency distribution caused by different vibration sources,the wavelet energy entropy (WEE) measu rement method is proposed based on wavelet analysis method. The WEE can descript the difference pe rformance of energy distribution quantifiably for signal decomposition scale,als o extract feature of the output signal and classify the output signal. The method can effectively distinguish the difference between the external envir onmental factors,such as mild disturbance,wind and rain,and the intentional invasion.The accuracy and real -time performance of the system is improved.The experimental results show that this method can evidently get rid of the non-intrusion disturbance,the system′s correction alarm rate is higher than 92%,and the false alarm rate is low.