Coupled-inductor based high gain quasi-Z-source inverters with continuous input current(CL-qZSI)can yield a higher boost ratio without increasing passive devices for the advantages of traditional Z-source inverter inherited. Topology derivation and working principles of the coupled-inductor based quasi-Z-source inverter are analyzed at length. Detailed comparisons of voltage stress of Z-source capacitors and diode are made and the effect of turn ratio and shoot-through duty cycle on the boost factor as well as the volume of coupled inductors and performance of CL-qZSI topologies are treated. The principle based prototype in the lab has verified the correctness of theoretical analysis. This work is supported by National Natural Science Foundation of China(No. 51577164).