A new direct peak DC-link voltage control strategy of Z-source inverter (ZSI) is proposed. For ZSI, the peak DC-link voltage is the actual voltage fed to the inversion stage. Controlling the peak DC-link voltage at the constant level can effectively decrease the voltage stress and simplify the design process of the inversion stage. A direct peak DC-link voltage detection method is developed with a simple sampling circuit, and then controlled directly. Therefore, the constant peak DC-link voltage can be achieved in different input and load conditions. The peak AC output is calculated in real-time by sampling the AC phase voltage, and it is controlled to the desired value without steady-state error. With the proposed direct peak DC-link voltage control and the peak AC output control, both the peak DC-link voltage and AC output are controlled to a desired level under different input and load conditions. Experimental results demonstrate the feasibility of the proposed control strategy.