Abstract: In view of problem of inherent delay of digital system caused by digital controller used in active power filter, the paper proposed a current control method of model predictive and applied it to control system of three-level active power filter. The method designs quality function based on the actual active power filter model, evaluates twenty-seven voltage vectors of frequency converter at each sampling interval, and selects a voltage vector which makes the quality function smallest to control switch conduction in the next sampling period, so as to make the compensation current of active power filter track the reference value rapidly. The simulation results show that the method of model predictive not only can make active power filter realize high performance compensation, but also reduce inherent delay of digital system.