A Sigma-Delta (Σ-Δ) analog-to-digital converter (ADC) and operation method thereof are provided. The Σ-Δ ADC includes a Σ-Δ modulator, a dynamic element matching (DEM) circuit and a control circuit. An input terminal of the Σ-Δ modulator is configured to receive an analog signal. The Σ-Δ modulator is configured to convert the analog signal into a digital signal based on a feedback signal. The DEM circuit is coupled to the Σ-Δ modulator to receive the digital signal. The DEM circuit is configured to perform a DEM algorithm on the digital signal to generate a feedback signal, and provide the feedback signal to the Σ-Δ modulator. The control circuit listens to the digital signal to detect a mute period. The control circuit disables the DEM circuit during the mute period to suspend a progress of the DEM algorithm.