Research has been conducted on the issue of high price and inconvenience in use of laser vibration measurement system. A low?cost prototype of all?fiber laser vibration measurement system is developed by using 1 550 nm mature narrow linewidth light source and optical fiber components. In the optical path part, a heterodyne laser interferometer is built using Mach?Zehnder interferometer struct ure, the reference light is modulated by a 40 MHz acousto?optic modulator and interferes with the measurement light on the photodetector surface to produce the original laser Doppler signal. In the signal demodulation part, the phase demodulation method is used to demodulate the original laser Doppler signal to obtain the motion characteristics of the vibration target, including the displacement, velocity and acceleration information. The performance of this prototype is tested with the vibration standard device in our center, and the experimental results show that, the measurement errors of peak displacement, velocity and acceleration of this 1 550 nm all?fiber laser vibration measurement system are within the range of -0.6% ~ 0.7%, in the medium to low vibration frequency range of 10 ~ 2 000 Hz. This system has both high measurement accuracy in medium to low vibration frequency range, and relatively low cost, convenient operation, which has technical reference value.