This paper proposes an improved model predictive control (MPC) for quasi-Z-source inverter (qZSI) without the use of the weighting factor. First, the inductor current is controlled by its subcost function to prejudge the shoot-through (ST) state, therefore the computational power is saved. Then a new cost function is designed. As the capacitor voltage and the load current have the same order of magnitude, the weighting factor is avoided. Lastly, the effectiveness of the proposed MPC method is validated by MATALB/SIMULINK.