In view of Z-source inverter diode current interruption resulting in DC link voltage distortion under the conditions of low power factor or small Z-source inductance value, studies a capacitor-assisted enhanced quasi-Z-source inverter (qZSI). Analyzes the cause of the Z-source inverter abnormal operating states and simulates the capacitor-assisted enhanced qZSI and the traditional qZSI by Matlab/Simulink. The results indicate that the proposed qZSI can better solve the problem of the DC link voltage distortion under the operating conditions of low power factor or small Z-source inductance value, and it improves the output voltage of Z-source inverter effectively and simplifies the inductor design.