A nonlinearity model including distortion components for sigma-delta (ΣΔ) accelerometer that allows stability analysis is described. Based on this model, closed-loop stability and signal dependent stability are analyzed detailedly. To verify the conclusions, Matlab/Simulink model for a fourth-order ΣΔ accelerometer is designed. The simulation results indicate that high-order system needs a large compensation coefficient, and it will not affect the performance due to the very high low-frequency gain of the loop filter. High-order system is conditionally stable, and stability is affected by the input signal.