The vibration reconstruction method based on laser self-mixing interference needs to estimate the optical feedback level factor and the line-width enhancement factor. In order to improve the precision and robustness of vibration measurement, a vibration reconstruction algorithm based on the frequency modulation characteristics of self-mixed interferometer is proposed. The all-fiber Mach-Zehnder interferometer is used to obtain the frequency-modulated signal of self-mixing interferometer, and the instantaneous frequency of the laser is calculated. This method does not need to estimate the optical feedback level factor and the line-width enhancement factor, greatly simplifies the measurement optical path and the solution model, and reduces the complexity of the vibration information extraction while ensuring the measurement accuracy. Numerical simulation shows that the proposed algorithm has good linearity in the measuring range from 2 μm to 100 μm amplitude with moderate optical feedback level. Experimental results show that the standard deviation of repeated measurements is less than 15 nm and the non-linear error is 0.78% in the range of 1.6 μm to 8.3 μm amplitude.