Aiming at the problems of low positioning accuracy, low sensitivity and high false alarm rate of distributed optical fiber vibration sensor in the market, this paper proposes a fiber optic micro vibration sensor based on double Mach-Zehnder(MZ) interference principle, and introduces the structure of the sensor, coherent detection technology and intrusion events pattern recognition technology. The experimental results show that the single trigger detection rate of the sensor is more than 99.7%, the multiple trigger detection rate is equal to 100%, and the single false alarm rate is less than 1%.