Deadbeat control as a discrete system control method is widely used in active filter control system. But without the prediction deadbeat control is actually a difference a beat or two beats control, for this, the paper proposes a prediction based on adaptive line enhancer for active filter deadbeat control, accurate predicts system state after two beats with the historical datas. Theoretical derivation proves the adaptive prediction method’s robustness is optimal in the sense of H∞, experiments demonstrate that the proposed method is correct and feasible.