The effect of head movement on the performance of active noise control headrest systems in reverberant sound fields is investigated in this work. Based on the rigid-sphere scattering model， the performance of active noise control headrests in reverberant fields is analyzed. A prediction formula for noise reduction degradation due to head movement is proposed through numerical simulations， and the accuracy requirements for ear positioning systems applied to active noise control headrests are discussed. Comparisons are made with the case where the primary noise is a plane wave. Simulation results indicate that higher frequencies， greater initial noise reduction levels at the head position， and larger movement distances lead to more significant degradation in noise reduction. For 125 Hz， 250 Hz， and 500 Hz， with an initial noise reduction of 20 dB， the allowable head movement ranges to ensure noise reduction degradation not exceeding 3 dB are 3.1 cm×4.1 cm×1.4 cm， 2.9 cm×2.5 cm×1.2 cm， and 1.4 cm×1.2 cm×1.0 cm， respectively. These ranges are smaller than those for plane wave incidence， which are 3.4 cm×9.1 cm×1.7 cm， 3.1 cm×4.8 cm×1.5 cm， and 1.9 cm×2.3 cm×1.1 cm， respectively. Finally， experiments conducted in a reverberation chamber to validate the simulation results. The findings in this study provide guidance for the design of active noise control headrests applied in reverberant acoustic environments such as aircraft cabins and train compartments.