To solve the issues of insufficient memory and low processing speed caused by excessive data volume in low-frequency calibration under existing calibration methods, a low-frequency accelerometer calibration system based on homodyne laser interference is developed. The error-compensation method is proposed by analyzing nonlinear errors, particularly the non-orthogonal phase error. Using the dynamic successive phase unwrapping method and the self-adaptive dynamic decomposition algorithm for data acquisition and processing, the sampling rate and data volume are reduced, and the calibration accuracy is ensured. Experimental results show that the system can achieve high-accuracy sensitivity calibration of the accelerometer in the frequency range from 0.1 to 80 Hz and satisfy the test requirements of low-frequency calibration.