In an optical fiber perimeter security system, the longer distance and background environment complex border detecting, the system based on optical fiber cable line implements the event recognition. In order to distinguish the various induced cable vibration excitations, according to the intrusion signal and environment caused by vibration signal in wavelet scale above difference amplitude distribution characteristics, by using wavelet multi-resolution analysis theory, the scale variance component of feature vectors is constructed. According to the variance feature vector, scale- variance signal method for identifying different kinds of vibration signals is proposed. In the experiment system, total cable length is 56 km, the power of the light source of 300 μW, working at a wavelength of 1 550 nm. The experimental results show that the method can effectively distinguish the intrusion signal noise, environment and human activities caused by non -invasion, improve the detection probability and reduce the false alarm rate.