Active power filter (APF) is one of the effective means to eliminate the grid harmonic current generated by nonlinear loads. This paper proposes a compound controller based on model predictive control under three-phase static coordinate. The compound controller consists two parts including improved adaptive generalized integrator and model predictive control. The composite control strategy effectively integrates advantages of adaptive generalized integrator and the model predictive control. Steady-state error is conducted by the adaptive generalized integrator under each harmonic current tracking control, at the same time model predictive control is used to track harmonic current at fastest speed. The proposed composite controller combined with three-level voltage space vector phase modulation can eliminate the steady-state error which exists only using the model predictive control strategy and improve system robustness. Detailed study of the composite controller design method is given, as well as the parameters of the system design and stability analysis. Effectiveness and correchness of the control method proposed are finally verified by experiments.