The study of model predictive control（MPC）on a pulse-width modulation（PWM）rectifier is mainly implemented under the condition of ideal balanced grid voltage at present，while few investigations are reported on control under unbalanced grid voltage.Thus，this paper proposes a new model predictive direct power control（MPDPC）for PWM rectifier suitable for operation under unbalanced grid voltage，which is aimed to eliminate the double grid frequency oscillation in active power and ensure sinusoidal grid current.Compared with conventional MPC，only one compensation block is required to be added to the original power reference.The calculation of the power compensation has no need of rotary transformation and positive and negative sequence decomposition of grid voltage/currents.It has the advantages of simple principle，easy extension and strong robustness，etc.Simulation and experimental results have verified the effectiveness and feasibility of the proposed method under unbalanced grid voltage.