An all-optical fiber vibration detection system based on optical fiber laser ring cavity to detect high frequency weak vibration signal is presented. A micro-fiber Mach-Zehnder interferometer with multi-channel comb filtering characteristics is formed by tapering polarization-maintaining fiber by fused taper technology. Combined with the fiber laser ring cavity system, MMZI achieves dynamic response to vibrating sound signals in the frequency range from 200Hz to 20000Hz., and the minimum detection pressure of noise limit is 6.44mPa·Hz-1/2. The sound frequency response range of the unconnected fiber laser system is 200Hz to 4 000 Hz and the sensitivity is 29.36mV·Pa-1. After being connected to the laser system, the sound frequency response range is expanded by nearly 5 times and the sensitivity is increased by 6 times, which provides an effective method for broadband sound detection system and micro optical signal detection technology.